I (stupidly) used to wash out DD's plastic bib after meals and hang it on the back of hte high chair to dry...now there are some mildew spots on it (at least that is what it looks like to me) Now I drape the bib on the faucet....wish I would have done that in the first place. I sprayed stain remover and washed it and they are still there...what can I do?