Oh my goodness, crafters, I have NEWS! The plastic in the window of a business envelope is shrink plastic!
Check it out - I've stamped a nice outline flower, and shrunk, once without colouring, and once with pencil colouring. There was a third one that looked awful - not all the plastics are the same.
A tip - leave the plastic on the envelope while you stamp and colour, and cut it just before shrinking.
There you are - go to it!
2 hours ago