A few years back, we introduced fuel tank vent filters as a simple step toward drier fuel (see Practical Sailor January 2013, EPA Mandate Sparks Fuel-vent Filter Test and PS January 2014 Diesel Tank Vent Filters). The caveat was that eventually the resin would need regeneration.
We wished they could be as maintenance free as the carbon canister on your car, but they lack the regeneration cycles programmed into your car. The makers say the silica gel resin should be replaced annually, but Practical Sailor testers have found that three years is about right for diesel and five years for E-10 gasoline.
At that point the gel turns from blue to pink as it becomes saturated with water and regeneration with heat is needed. Note that some pink in the filter is fine; it is only when it becomes nearly all pink that it is spent.
The rejuvenating process is as simple as dumping the resin in a pan and heating over a low flame while stirring periodically. To avoid overheating the resin, the flame should regulated such that the process takes about 20-30 minutes.
Although we regenerated the resin for this gasoline vent filter on grill, other testers actually used galley stoves and reported no noticeable odor in the cabin. Practical Sailor recommends the outdoor grill, just to be safe.
If your filter material is wet or contaminated with fuel, you should revise your installation, either by moving it to a higher location, or adding a cover to prevent water ingress. These beads can be rinsed, dried and reused. After heating, let cool and you are good for another three to five years.