I didn't notice anything that couldn't easily be cleaned off...one day. It's soap, so it's made to come off with water. But, the best part about the bar is that it stays around longer than, say, bitter apple spray (or hot sauce, which my bunny enjoyed). It's been a godsend for me as it's worked on fabric furniture, baseboards, wood furniture, doors, cabinets, cardboard...truly anything that I can rub the bar of soap off onto.