I was listening to the lovely Phil last week and he was on about his range of stamps and the different qualities of Polymer that there are. He said he uses Grime Boss (or Buster ?) wipes on his stamps and hands and has no staining at all, he said its because of the quality of the Polymer he has them made of. Might be of help to someone ?!
(I have no idea what I'm talking about really - I have a box full of unused rubber and poly stamps that peeps have bought or passed on to me.........must put it on my roundtuit plate - but its rather full already !)