If by "cling" stamps you mean "clear" as opposed to the cushion with cling vinyl, then they are probably made from photopolymer. As the "photo" part of the name implies, they react to light, mainly by yellowing. It does not affect the quality of the stamp itself or the stamped image - it's just part of the deal. However, you should read the care instructions from the manufacturer to see if there are guidelines as to what to avoid. None of the clear stamps or cling-vinyl stamps play well with acetate, so definitely avoid that! There's nothing you can do to "restore" them to their non-yellow condition, though, as far as I know...
Originally Posted by lisasmith54
I have been buying mainly cling stamps lately because they save a lot of space and are cheaper, not to mention not chopping down trees for mounts. I have noticed on one set of older clings that they are starting to yellow. Does this mean they won't stamp right and is there a way to restore them? TIA, Lisa