What's your favorite solvent for cleaning carbon?

Tore down my engine (after a cam chain guide disintegrated, but I digress) and wanted to clean up the pistons and valves. I went to the local auto parts shop and got a gallon of Berryman's Chem Dip, which I recall doing a damn fine job on carbon last time I used it—which was a while back. I guess they must have changed the formula, because it's not doing much to break down the carbon buildup at all.
Has anybody used other products (Carbon-Off, Carbon Kleen, etc) and, if so, do you have a favorite?

Thanks in advance,

Buzz

Methyl ethyl ketone (MEK)

MEK wouldn't have occurred to me—plus it's something I've got on hand for paint cleanup.

Thanks!

If MEK doesn't work I'd go back to the carb dip, but this time leave the parts in the sauce for a longer time.  How long did you leave it anyway?  

I’ve had good luck with Berrymans. As Nessism mentioned patients is your friend. Unfortunately I didn’t get a picture of these before I started. The fugly one is after a couple of soaks and gentle scrubbing with a brass wire brush. The clean pic is the finished product.

Left them in for a couple hours without much results, then 24 hours with a little better results. Finally, after another 24 hours and a good deal of elbow grease, they cam out pretty okay. I recall this stuff working better than that, but maybe I had more patience when I was younger.

I was reading on a gunsmith forum that they recommend piston Kleen. It’s used to get carbon out of the inside corners where the land meet the grooves. I have never tried it. 

orisonmarketing.com/products/piston-kleen ™

I just cleaned up a set of pistons and valves in my ultrasonic cleaner.  I use a detergent from Caswell.  Works good.  Takes about an hour.

Soda- blasting

WD40 and gentle elbow grease

 

Ive rebuilt tons of two strokes so Im used to carbon buildup.  Years ago it was Permatex spray gasket remover but they changed it around 2006.  Spray oven cleaner works just as good.  Spray it on, let it sit for a bit then clean.  Follow up with mineral spirits.

I started this 15 yrs ago here! Marvels Mystery Oil! Mixed with either lacquer thinner? Acetone or Mineral spirits!
I always used Lacquer because I had it as a painter! It does evaporate as it sits.
but only way! Scrub it off with nylon, plastic, soft abrasives!
then media blast with fine glass beads!
I’ve only been doing this for 40 yrs.
Carbon on Valves! Tops of pistons!
clean them 1st. Whatever? I’m old and done! Worked for me!  You need Air! And tools & equipment! At least this is me! What I did for the past 45 yrs.