Was this when you were actually felting the bag, or were you washing an already felted bag?
It is always recommended that for felting, you put your project in a pillowcase so that the lint doesn't clog your washing machine. It's apparently normal for things to shed like that during the felting process.
I'd say, if it was a washing after the initial felting, I'd definitely put it in a lingerie bag or pillowcase for future washings!
No, I was washing it to felt it. I put it in a pillowcase the first go round. I was warned that SWS felts a heck of alot faster than other yarns.
It took me three cycles! The second and third time through I switched to a lingerie bag.
Now that it is stuffed with grocery sacks and it drying, it is starting to look less like a drowned cat which is always good when you are talking about a purse.
I think I'll try a lint brush when it is done drying.