Yah, twisty-ties, I had to take one away the other day. Felt bad they were having such fun with it
, so we had a play session with the teaser.
Generally it's like a 2-year old child rule---if it's something they can reasonably swallow whole, or chew up into pieces and swallow, then they probably don't need to have it unsupervised. Pipe-cleaners (chenille) are usually pretty big, especially if you sorta twist 'em around and join the ends and I don't think they can really chew through them (I have to use dikes to cut them) although I would check them occasionally to make sure about that because I suppose it is possible if they really tried they could eventually get through the metal.