Personally, I wouldn't let her near them.
Things like that can get wrapped or lodged in the intestines and cause things like bowel obstructions.
Take it from someone who had a garbage can dog at one time.
The best thing is to keep these things up and out of reach.
I would take her to the vet if she has eaten anything that isn't food and hasn't passed it yet.
She may have troubles when she is straining to do so later.
But others might have good advice too.
I saw (on Animal Hospital once) a cat in the surgery who had swallowed a piece of elastic. It had lodged in the gut, and was all twisted round. The vet had to cut open the guts in several places to get all the stuff out. It was a big operation, so I would also advise you not to allow your cat to play with this kind of thing.
I have a cat who likes elastic, cotton thread etc. and do my best to keep them away from her. But she will delve into the bin and steal bits if she can. Just recently I saw a longish thread hanging from her bottom, and I gently pulled it out (luckily it had passed through her without getting stuck). As it cleared her backside it pinged off her - she did look outraged!
Very dangerous play toy as had been said. Get a small tupperware container and keep them inside with the lid on. Pray that what your cat has eaten has passed, but if you know she has been indulging in these, I would suggest you get her to the vet for an x-ray just to be safe. Rubber bands, dental floss, hair ties, milk bottle strips, all are dangerous for kitties to chew on and eat.
My boyfriend's cat loves those garbage twist-ties. He likes to pounce on them. We only let him play with them while we are watching so that we can take them away if he starts to ingest one. Cats are like small children--some of their favorite toys require supervision.