I have two cracked asbestos shingles on a very steep pitched roof. I want to repair them but I am uncertain whether I can get on the roof at all and what material would be most effective in filling in the cracks (caulk, tar ???). Any help on either of these questions would be appreciated. In the event I destory my roof, may "regular roofing firms remove asbestos/cement shingles or must a special roofing contractor be called in. Thank you.