The roof of the RV, in my case the fifth wheel fiberglass cap, demands a little more specialized cleaning. This is where during road travel all the bug abuse takes place. Sometimes the carnage can be enormous! The best defense against super stuck on bug guts is a very well waxed front cap. The best method I have found to remove the squashed little buggers is with a dryer sheet. First wet down the area and the dryer sheet and if you have a decent wax underneath they will come off fairly easily. To access the higher areas just put the dryer sheet under the brush and scrub.