The Ultimate Guide to Caring for Clear Plastic

Posted by Darrell Nicholson at 12:53PM - Comments: (9)

Practical Sailor tester Drew Frye polishes the clear windows on the dodger of his PDQ 32 catamaran being used in our test of clear vinyl brands, and clear-vinyl cleaners and protectants.

Look at any boat more than five years old, and chances are, the clear dodger windows aren’t so clear anymore. By comparison, the windows on one of our test boats remained crystal clear for 15 years. Is clear vinyl really that vulnerable, or are boat owners doing something wrong to shorten its life? The answer to both questions is, "Yes."

One of the best known manufacturers of clear plastic windows for dodgers and cockpit enclosures is Fort Lauderdale-based Strataglass. The company has perfected a highly scratch-resistant coating for clear plastic, originally intended for the automotive industry. It has since become the product of choice for high-end yachts.

Strataglass recommends using its own Strataglass-endorsed cleaners and protectants, made by Imar. These have done well in our previous tests of clear plastic cleaners and protectants, and the prices aren’t significantly more than competing brands. But as usual, we remain skeptical—and curious. What about homemade cleaners, like our anti-mildew concoction that is 35 times cheaper than what you buy at West Marine?

With the hopes of finding a cheaper way to protect our $150-plus Strataglass dodger windows, we tested other cleaning products and protectants on the company’s two types of clear plastic. Two years into the test, we found that other non-Imar products—as well as some combinations of products—effectively protected Strataglass. 

Strataglass online user’s maintenance guide states the following: 


  • Use Windex, Rain-X, Pledge, Plexus, Simple Green, Orpine or any other harsh cleaner to clean Strataglass products. This will void the warranty.
  • Use a car wax or any kind of wash and wax to protect Strataglass products. This will void the warranty.
  • Use cleaners, polishes, scratch removers, or any products intended for commercial grade vinyl or plastic. This may damage the Strataglass and void the warranty."

In addition to Strataglass' warnings, we were surprised to find that some everyday products—including sunscreen, bug spray, canvas treatments, and mildew cleaners—can do irreparable harm to Strataglass.


There are many common boating chemicals that can ruin vinyl windows and are rough on other plastics:

• Sunscreen: Sunscreen handprints on vinyl are difficult or impossible to buff out. Sometimes, the handprints occur when a guest helps roll up the windows, and you may not see them until the next morning, when dew “develops” them, inside the vinyl. Keep a washcloth handy for wiping hands, or better, wash hands before touching the clear vinyl.

• Insect repellent: DEET will melt vinyl. Even a fine spray will haze many plastics. We recommend politely asking guests to use insect sprays well outside of the cockpit area, away from all windows, and to wipe or wash their hands thoroughly when finished. Consider banning aerosol bug repellents from your boat.

• Vinegar: If rinsing your vinyl windows with fresh water and polishing them with a spray polish does not remove all of their spots, the spots are very likely calcium deposits. Use a 10-percent solution of vinegar and water to clean them, rinse thoroughly after use, and apply a protectant.

• Canvas water repellents: As we reported in the December 2013 issue, some canvas waterproofing treatments are quite tough on vinyl and can ruin it within minutes. If you treat your canvas, be certain to apply a fresh protectant coat to the windows before you begin, cover the windows, and then wipe the vinyl with a cleaner/protectant after you are finished.

• Silicones and solvents: All manufacturers advise against using products on vinyl that contain silicones, petroleum solvents, or alcohols. Small amounts of certain alcohols are permitted in some cleaners but not the use of alcohol-based glass cleaners.


Covering clear-vinyl windows offers fool-proof protection from harmful UV and dirt. The downside—other than cost and the added time before and after sailing—is the risk of abrasive wear between the cover (typically Sunbrella) and the window. We’ve heard of folks using textured Phifertex covers and finding that their windows have a fine checkerboard pattern within six months. We’ve also heard reports of damage in windy harbors from the covers constant flapping; in the wind, the best solution seems to be consistent cleaning and use of protectants.

Some folks use Sunbrella with an integral lining, but dirt can imbed in the lining, resulting in worse abrasion than plain fabric. Wear is very often related to the size of the dirt particles, and lined Sunbrella can hold larger particles than unlined Sunbrella.

For the best of both worlds, we suspended awning covers over the dodger windows. There’s no chance of abrasion even if the window is salt- and dirt-encrusted; UV and bird bombs are blocked; and they can even provide expanded shade and reduce the need to close the windows for a passing shower at anchor.


Use only soft polishing cloths to clean clear vinyl. Clean cotton jersey (T-shirts or polishing cloths) are safe, but paper towels may leave scratches (grit left over from the paper-making process is much harder than vinyl). Microfiber cloth is a favorite as well, but it must be kept very clean as it quickly attracts dirt.

Rinse the windows with water before polishing, and change to a fresh cloth every 5 to 20 square feet, depending on how clean the window was at the start. Turn the cloth frequently.

Storing Windows

Only roll up vinyl windows when they—and your hands—are clean. Salt spray is abrasive and can cause minor scratching. It’s better to squint through salt-encrusted vinyl until a freshwater rinse is practical than to have your view blocked by scratches for years to come. A handy fresh water squirt bottle can help rinse at sea. Alternatively, remove the window panels. If you’re rolling up the windows for storage, roll them with soft, clean fabric to keep the vinyl from touching itself and potentially abrading the surface.

If you plan to roll up your windows regularly, you’ll likely be happier with a thinner vinyl material (30 mil vs. 40 mil) or more flexible products (O’Sea and Regalite, vs. the stiffer Strataglass) since less force is required and less scratching results.

Cold Weather Care

While many folks put their boats away for the season as soon as they need socks, some sail into the fall or even year-around; the further north, the greater the urge to stretch the season. As temperatures plummet, we become more and more accustomed to the chill, and by January, some think 32 degrees is quite comfortable for a day on the water, if dressed for it. However, vinyl does not acclimate, and depending on the gauge—thicker is stiffer and more vulnerable—rolling or flexing old vinyl windows at temperatures below 60 degrees is just asking for trouble. The more worn and hazed the windows become, the greater the urge to clear the view by rolling them out of the way, and suddenly the window has a crack running halfway across. A good rule of thumb is to wait to roll windows until hats and gloves are forgotten (over 60 degrees). If there is dew or frost on the windows, wait for the sun to remove it.

Scratch Removal Products

Our early testing suggests the actual vinyl-restoration process might compromise the material’s protective coatings and lead to premature weathering, even if applied to just a few scratched areas. We’ve added some “restored” windows to our long-term test racks, but it is clearly better to keep windows scratch-free and UV protected than to restore damaged vinyl.

If your vinyl windows have some damage or weathering, and standard cleaning and polishing is not doing the trick, try laying them on a flat, towel-covered surface and polishing very firmly with Imar Protective Polish. This was effective in removing light oxidation and providing deep cleaning as the polishing, without the risk of abrasion or coating degradation. For a more complete report on specific products, refer to our recenttest of clear plastic restorers. That report also compared the the value of a professional restoration as compared to a do-it-yourself solution.

Comments (9)

As I have posted on other articles, to keep your clear vinyl curtains scratch free and clear
checkout Clearstow boat curtain storage bag at

Posted by: canvasguru | January 31, 2018 7:44 AM    Report this comment

As I have posted on other articles, to keep your clear vinyl curtains scratch free and clear
checkout Clearstow boat curtain storage bag at

Posted by: canvasguru | January 31, 2018 7:44 AM    Report this comment

This method was recommended to me by a sailor who also had a canvas business operated out of his boat in Europe. He told me that the best treatment for my strataglass was to take it down, lay it flat, wet it down and then soap it up real well with a dish soap solution, and let it sit on it for about 15-20 minutes. The strataglass will absorb some of the fats from the soap. Then rinse. This actually does help to clean, maintain the gloss and lifespan of the plastic. Works just as well, if not better than the expensive products. Turn them over and then do the other side.

Posted by: Sailing gal | October 26, 2017 2:37 PM    Report this comment

Add our experience with sunscreen clouding the vinyl windows, especially the spray varieties. We had immediate and irreversible clouding from a single episode of sunscreen overspray. Now we don't allow spray sunscreen or insect repellant on board.

Posted by: H dock | October 26, 2017 11:27 AM    Report this comment

Our clear plastic dodger windows were so old and opaque that I had nothing to lose in being aggressive in restoring a clearer view. I used "Star brite, Step 1, Clear Plastic Restorer". After first washing the dodger with dish soap, I set a clean soft towel on a flat platform then placed the clear dodger window on top. Using an electric palm sander, wrapped in a soft cotton towelette cut from a small towel, I buffed away and was impressed by the scratches that disappeared and to the visibility that was restored. Certainly not like new but far better than before. An experienced boat worker told me that automotive rubbing compound, not wax, will do just as well and is less expensive.

Posted by: PatrickChildress | August 9, 2017 1:20 AM    Report this comment

I've noticed this year with the excessive heat that a gray or fogging has occurred on my boat cover plastic windows. I clean them often with clear water and a little mild detergent. At the end of the summer season I store them inside. Do you have any suggestions on restoring the windows to a clear view. The plastic windows are 10 years old.

Posted by: Harry orlando | September 24, 2016 10:30 AM    Report this comment

TSP is agressive towards almost any material that is shiny, glossy, amd smooth

Posted by: Unknown | January 5, 2014 10:45 PM    Report this comment

The washing soda and borax based anti-mildew formulas were intended for cabin use. These DIY formulas are water-soluble, so although they might work on the underside of a canvas dodger, they will likely rinse away from the top in the first rainstorm. Nevertheless, we have since tested these, as well as 3M and Goldshield anti-mildew formulas on Strataglass and Regalite. Applied in the normal manner and allowed to dry, ALL of these will cloud vinyl windows. However, if exposure is limited and they are rinsed off before drying, no damage should occur. We have seen this same type of clouding damage caused by every highly alkaline cleaner; windows should be cleaned and polished only using products specifically formulated for vinyl windows, and at this time our recommendation is to stay with Imar products.

Posted by: sailordn | December 13, 2013 10:14 AM    Report this comment

Would the mildew cleaner (TSP, baking soda and sodium carbonate) solution harm the strataglas, if some were to drip from the canvas onto the window?

Posted by: George C | December 11, 2013 10:18 AM    Report this comment

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