Sticky Stuff Remover available from Betterware was mentioned in Ian Billings reply to my post " Removing Self Adhesives from Paper"
I tried soaking another 1st class Large today in saucer of cold water, with this I put it in the microwave on high for a few seconds. The stamp came away from the backing paper (fine) using a pair of tweezers, but again it left a gum residue. This I removed with neat alcohol and a cotton bud. This like Ians experiment left traces of gum around the security slits. To mess with it any longer would have destroyed the stamp.
I can see these security slits will prove to be a pain. Royal Mail has certainly done its homework. It is a pity they did not do it earlier regarding the cancelling of stamps used in the mail. Over the last six months or so I have the total £8.47 in used stamps, over 75 stamps of variious denominations which have arrived on incoming mail without a cancel. They are still arriving as with the letter from The Modern British Philatelic Circle (over £1 in stamps uncancelled) which arrived this morning.
By the way if you are reading this many thanks go to Keith Woodward and Tony Wilkins for your quick replies.
Any comments or more bright ideas for removing these issues? We still need to hear from you on this subject.