Baby sucking on washcloth?

When I give my 5 month old a bath, she likes to take the washcloth and suck on it. I'm not too worried about her swallowing the little bit of water, because I wring it out before giving it to her, I'm just wondering about the baby wash/shampoo that's in the water. I read the bottles and neither of them have any cautionary information (as in "do not ingest"), so I'm thinking it's fine, but I don't know! Any thoughts?