stacking components without leaving marks

I used to have a 70 pound concrete patio circle i used as a base for a stacked pile of components. Under the painted patio slabwere TipToes. Then the stack of sstuff with the amp near the speakers.
hat was a nice setup.
I now have racks from a 'big box'store i filled the tubes with playbox sand. Due to the tempered glass shelves, i use butyl rubber bottle stoppers a lot. Size ten.
I like the rack I now own, andsince i paid only about $150 each for them, they area great deal for the cheapskate i am.
I have two TVstyle racks, and one tall one. One TVstyle has the Plazma TVand the receiver, and the DVD players, then the other TV style rack has the two turntables on it. The tall rack has my two channel stuff, with the amp over by the speakers.

almost forgot about this thread, wow what a lot of comments! thanx guys! i was always under the assumption that felt left marks, i will get some.

Plastic wrap works well. I use circular sorbothane pads in place of, or underneath, the feet of some components and apply a piece of plastic wrap to each side of the pads, then loosely trim to fit with scissors. It sticks to the sorbothane so it's easy to adjust the position of the pad and the sorbothane is a good isolation medium.