Replacing my Intake Manifold Question

What do you guys use to cover the lifter valley while I clean the intake gasket area to keep all the junk out?
paper towels. i have a GIANT roll of the heavy blue towels (thanks U-line!) and they work great. i lay those down in the valley and then lightly stuff the ports so nothing drops in there.

vacuum while you're pulling everything up and taking the towels out of the ports so nothing jumps in anywhere that it's not supposed to be.

work diligently and delicately and you should be fine.