The clear is just not fuel proof enough, not even fuel resistant. Common thing these days and a million line shave been written about this in the forums. Most guys these days put at least a light coat of two part automotive clear on at least the nose and fuselage around the wing leading edge. Some do the whole model. You mentioned wax and you may want to try some good wax on the nose area as a couple of coats of wax may help if you don't want to try the 2 part stuff.
Type at you later,
Dan McEntee