I would not recommend keeping your coins in those for a long time. The softer plastics may contain PVC which will damage your coins.
Don't read too much into this. You don't need a 1,000 psi filtered, purified, and ionized air system. I use cans of compressed air that you can get at Wally World or any photo store. If microscopic cardboard residue is left on the mylar, I'm not going to notice it.
Thanks, good to be here. Don't tell anyone but I pinch my compressed air from work. We need to talk radio sometime. -.-
The problem is Jack your coins might notice it. With circulated coins, it's not that big of deal. But with higher grade MS or Proof coins it is. Those fine pieces of cardboard dust will create hairlines and can even scratch the surface of a coin. That's why I never recommend storing higher grade or Proof coins in the cardboard flips.