Personally I am not a fan of ordinance under an a/c but I have read many times here that using the little rubber bands used for braces are very handy in masking off the bands on bombs and missiles. Just in case... I asked my daughters Orthodontist for some and he gave me about 15 packs of different sizes. So if I ever do hang a bomb... I am ready.
Painting should be treated like any other part of the a/c. When weathering, ordinance should generally be cleaner than the plane