i am in the process of doing a semi rebuild on my engin. new main seals and hg, head studs adn valve stem seals. my questions is whats the best method cleaning the block surface before putting on the new head gasket. im not dropping the pistons out so how should i protect the bores and debire from falling into the water jacket. can anyone offer any advice. im really trying to avoid a trip to the machine shop because the block and head was just recently decked. thanks. john.