Everything the others have said, I quit using Mono about 15 years ago when they changed it, the problem was a hit and miss thing, some colors shrunk well and others didn't shrink at all.The older ARFs would look great when they left the factory but often the temp differences, humidity and moisture caused the covering to wrinkle and sag during shipping. I have assembled ARFs for people and had some of the bubbles and wrinkles pop right out and others the iron had no effect. If the bubbles don't shrink up after using the pin and iron you are probably out of luck.