I have always diluted my Best Press. I have never had it stain, but I think it takes a little longer to iron the fabric dry when you dilute it. It works just as good as full strength and costs 1/2 as much (I'm cheap,too). It does make me cough sometimes, but I just hold my breath while spraying. All the scents make me cough, but not enough to make me stop using it.
Sue