What is the best way to get the self adhesive deck patches off?
A Carefully peel back a corner and pull the material firmly away from the deck keeping it close down to the deck. With care it should be possible to take the adhesive with the cloth. Sometimes this will not be possible and areas of adhesive will remain stuck to the boat. Generally it is best to avoid trying to use solvents to remove this adhesive as they will only spread the material more thinly over a larger area. They may damage the paint and boat too. Instead use a small piece of deck patch material, perhaps some of the material you have pulled off, and stick its sticky side to the adhesive on the boat. Pull it off firmly. Keep doing this and you will find the adhesive is removed from the boat and picked up by the patch.
