Here in US you can tell someone how good it is but they will never believe you. I have acetone washed and nobody cared for it, and would still only buy the regular "off the brick". Only friends who trusted I did it would notice the difference but Oddly not pay for it. So IMO just do it for friends and yourself if your selling. Maybe you europeans are different though, I only fuck with weed abroad. Xan before the plane and wake up in EU.
In my experience they still wont pay more money, yeah they will tell you its good but still wont pay more than normal street coke. But hey everyone is different.
Depends on the country. In Ireland a bag off the street is 80 to 100, on the continent it is 50 or 60. So depending on where you're based I'd say 25 extra as its premium, and if you can get clients who prefer the washed stuff youll do well