> ... gotta love science.

Yeah - pays the bills, and is even fun sometimes.

> The buildup is not very severe in reality, just to me. I don't
> like to see that happen to any of my Yixing.

I shouldn't admit it in public, but that kind of residue really grosses
me out. Don't know why; I've handled so many more intractable, toxic and
nasty-looking messes professionally. Guess it's different when it's
food-ware. I've certainly learned the hard way to keep anything like
Yixing pots away from the stove, sink, and large concentrations of
plasticized PVC (like some bags and even cookware). It seems that just a
bit of oils and phthalates can cement together an astonishing amount of
dust, spiderwebs, insect droppings, whatever, into something horrible.

> I am going to try the Baking Powder. I'm hoping that will do the
> trick and if not I may move into the vinegar area but that will be a
> last resort as it kind of scares me. Any idea of how much or any
> particular type to use? I'm guessing any plain white household
> vinegar would be OK.

Exactly: white, distilled cider vinegar is pretty near pure aqueous
acetic acid. Since it's distilled, there's no residue after a good wash
and oven-bake. I'd use it straight.

I suggested alkali (like carbonate; should have mentioned TSP as well)
because it can chemically chop up the gunk by ester hydrolysis. Vinegar
would be acting mainly as a solvent. 6% acetic acid isn't a very good
one for that kind of thing, so I'd lean hard on the alkali first.

> I do work for a university so I could probably
> come by way of just about any chemical if you have any suggestions.

For solvents, MEK really is good - dissolves or softens most organics,
volatile with no residue, nearly non-toxic, cheap and available. If you
want to get more serious, chloroform will dissolve almost any kind of
grease. Could take some baking to get the sweet smell out, and many
people are worried (needlessly, IMO) about possibly mutagenicity. heck,
us oldsters (and anyone who's treated a cough in Europe) knows what
chloroform tastes like. Sodium carbonate or TSP are excellent cleaning
agents as well. Can only do much better by getting into dangerous mixes
like sulfuric peroxide. These "piranha solutions" essentially burn
organics just like fire.

> I have also read about using ultrasonic jewelery cleaners and this
> may be an option for me too if all else fails, anyone have any
> experience with that?

The home ones don't have much oomph; I have two and only use them for
friends' jewelry and fountain pens. If you have lab access, a
half-gallon Branson with warm water and a little detergent should rip
the gunk off in a few seconds. Awesome to watch. Throw in your
watch-band, too - you'll have nightmares about all the yuck that was
hiding in there!

-DM