There's evidence that human hair doesn't need to be washed at all and keeps its condition. I saw an experiment where someone stopped washing it and she said it did smell a bit sheepy after three weeks, but after six weeks it was in the best condition it had ever been in.

Baby powder. Put it in your hair and blow dry it while you comb OT out. It will absorb the excess oils and take them out too

The longer you go with out washing it the less oily it gets. And yeah therr are dry shampoos.

Dry shampoo is over rated. Baby powered will do the same thing. Just make sure you don't dump it on you head. Sprinkle it on you brush while brushing. :)