stacking components without leaving marks


as we all can see on audiogon, this is not as easy as it first appears. has anyone found a good solution (DIY or commercial) that can go under the feet of a component LONG TERM that can allow it to be safely stacked on another component? something that wont scratch or discolor the bottom component?
ratso1
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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.