Originally Posted by gregzgurl
The trick to shrink plastic is to let it go longer - eventually it does flatten out. I kept thinking that I was doing it wrong because all my pieces were so "wonky", but when I gave them more time they did much better... It also makes a difference if the shrink plastic is old, I think.
Another tip on Shrink Plastic is to keep a heat resistant flattener at hand (I use a bamboo cheese board I repurposed for crafting, or the bottom of a glass) and just press down on the item while it is still pretty warm - works like a charm. YOu can also always reheat repeatedly, if you were too slow to get it. I often use an oven, then just zap it with my heat gun for a few moments to flatten.