My DS often goes to spend time with my MIL and FIL. Every other time he comes back with visibly greasy hair (so greasy that it leaves stains on walls to give you an idea). I find it disgusting. I can't look at it without feeling nauseous. They have been putting some kind of hair oil (they said coconut sonething) which is fine, I've used marrocan oil stuff before but not enough for my hair to get oily! DS is only three and has perfect hair, he doesn't need anything in it! Each time this happens I have to give him a bath (unfortunately he has bad eczema so can't have too many baths, additionally visits tend to be very ad hoc so sonething it will be difficult to squeeze one in either because I have to take him somewhere (e.g. Doctors) or because it would mean delaying bed time, or he would have already had a bath that day so it would be really bad for his skin). I have tried dropping not so subtle hints (e.g. Noting to my son when they drop him off that his hair is very dirty as he should go upstairs to have a bath). Am I overreacting because I find it gross or would it be ok to ask my husband to tell them not to do it?