I used wax to seal the filler cap on my wing tanks so the filler, primer, and paint would not run in and permanently glue my caps on. I wound up smearing the wax when I sanded the filler and had all of the filler and paint peel off after I painted the wings for about two inches around the cap so be carefull that you don't get wax where it shouldn't be.
I found a spray can of wax remover at an auto parts store that I used before I repainted it and that took all the wax off. Scott Cable wrote: WD-40 would contaminate the composite. Use a real release agent or non-contaminating wax.
