Do you wash your hair to get out all of the gunk before you dye your hair? If so, do you do it the day of, the day before, two days before, etc.?
If not, do you find any problems with dying your hair with gunk in it?
What are the pros and cons of dying (1.) with freshly washed, (2.) with clean but not freshly washed (wash day or two before and just not add product, so that only sebum and environmental elements are in hair), (3.) or with producty hair?

I usually wash my hair the day before and make sure I don't add any product. I am okay with some scalp sebum as it might minimize the drying effects. If I can go an extra day after washing my hair, I will...However, due to work and timing issues, that's not always possible.

What's been your experiences?
That's right, I said it! I wear scrunchies!!

I am a sulfate washing, cone slabbing, curly lovin' s.o.b. The CG police haven't caught me yet.