Removing Poplar Sap From Vinyl Floor?

The sap from the little poplar buds has been tracked inside onto my bathroom floor. It is not sticky anymore and I have tried everything I can think of to remove the yellow stains; household cleaners, nail polish remover, methylated spirits, etc. but I fear they have permanently stained the light colored vinyl. It looks as though a dog has crapped all over the floor, and I haven't cleaned it. Has anyone got any ideas?

By Cathy O'C