bubbles on ears?

I have a cat around 2.5 years old. Around 6 months ago she developed "bubbles" on her ears. They don't bother her but they take away from her good looks and I'm a little concerned and wondering if anyone had any ideas on how to remedy the situation.

I have no idea what "bubbles" are. Do you have a picture? Maybe someone with some experience will chime in here.

They sound like blisters.  Whatever, I'd take her to my vets.

My vet hasn't seen her but he said that if they don't bother her then there should be no problem.
 

Thanks for your replies. S.N.E.A.K isn't scratching her ears more than usual and I don't think she has mites because her mom,George, doesn't have the same bubbles! My vet says if she doesn't overscratch then it should be okay.