A few years ago a friend stripped and polished this n12 for me. I think he soaked it in oven cleaner after taking it apart. I changed the bearing and response and it has been a great beater yo-yo ever since.
You can also put it in a ziplock bag with pebbles and put it in the dryer and that gives it a matte look.
I don’t advise that with a plastic ziplock bag and a dryer with the heat on.
Have you tried this? It seems that a ziplock bag wouldn’t hold up too well even with no heat. I think you may end up with a dryer full of pebbles. 
What you do is put the yo-yo with a few pebbles in a small ziplock bag. Then you wrap that bag. in a towel or a shirt and put THAT in a larger ziplock bag.
You can throw a few extra towels in to help with the thumping. This only takes about 5-10 minutes. Keep an eye on the dryer and the yo-yo and you should be fine.
You shoulda said so up front. 
I was just giving a general outline of the process, not step-by-step instructions.
I would hope that most people know not to just throw a bunch of rocks and metal parts into their dryer.
Again I want to point out that no heat should be on.
Don’t count on it.
