Some folks have figured out that the automated postal sorters don't need a full stamp in order to determine if the proper postage has been applied, that they work according to color. So even if you cut the stamp up into tiny pieces and reapply it to the envelope, it may still make it through the system!
Check out some of the fantastic results by Kim Rugg though I'm not sure if these went through the mail. LINK
And some others that did by John Spurgeon. LINK
