Take my advice, and never put owt in the loft in one of these. They have a self destruct date of a year or so after purchase, meaning they collapse into tiny static pieces of plastic that cling to whatever it is you're trying to keep free from dust.

Not to be confused with sensible biodegradeable carrier bags, which rot when you bury them. I've found out the hard way that Tesco ones are the worst for reducing into annoying flakes of plaggy. Asda bags seem like the type which take thousands of years for anything to happen to.

but at least you've saved the environment