I'm not sure of the best process to put on new numbers, so they don't fall off right away. I would guess, it would be wise to use a rag dampened with mineral spirits, to clean the glue residue, then dry, before applying the new numbers. -Would that damage the dacron's coating? Even if it did, sails that old probably have the coating damaged from wear.
Dunno. Just the other day I used 3M Super77 spray glue to re-attach the numbers. They seemed to stick pretty agressively, but I won't know for sure until next time I head out. This past Saturday there was no wind, and it rained all day Sunday. So... we'll have to wait and see.
Jim
