Knoll/Saarinen fiberglass back executive chair restoration (Paint Removal Help)  

I got a good deal on a set of 4 original Knoll/Saarinen fiberglass back executive chairs recently but the fiberglass backs and the black legs on the chairs were painted white. I got 2 of the backs to come completely clean with a pressure washer but the other 2 I'm having some trouble removing all the paint for some reason. I got most of the paint to come off the legs also with a pressure washer but there are still some white paint spots on them. I'm wondering if there is any kind of paint remover I could use that would remove the remaining paint and not harm the fiberglass backs and wouldn't remove the paint from the black legs?
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