This was prompted by a door latch mechanism covered in decades of gunk, but the question's more general; since my cleaning resources basically stop at a can of brake cleaner and a plastic basin, if I want to get something cleaned properly, where do I go?

There's a machine shop down the hill that probably has the sort of equipment that could get stuff clean, but what do I ask them for, and are they likely to be interested in one little grease-packed doodad?

You could ask them to throw it in their 'Parts Washer' which is like a giant washing machine. Sprays the parts down with hot, high pressure solvent. But most of those machines are really set up for engine blocks and heads. So they're really large.

But I would recommend cleaning them at home. WD40 is actually a great solvent that also lubricates.
If you anticipate doing a bunch of cleaning a gallon of carb cleaner will allow you to soak the parts to allow the solvent time to penetrate. Berryman's used to be available locally. Don't know if the CA EPA has shut that down or not.

And finally, you can send them out for zinc plating and they come back clean as well as shiny.

I bought an ultrasonic parts cleaner for about $80 at harbor freight.

http://www.harborfreight.com/25-liter-ultr...aner-95563.html

I even ran it with denatured alcohol when I rebuilt the carbs.

+1 for the HF ultrasonic. You can't put LARGE things in it, but it does a great job on most of the stuff we have to clean.

I ran it with 50% water, 50% Simple Green and that got a lot of the gunk off. Then I'd spray them down with water, dry everything with a heat gun or hair-dryer, and then hit the parts with WD40 to keep things from getting gross again.

Just be careful using simple green with aluminum.

This product has been through Department of Defense
(DOD) testing and was determined to be highly corrosive
on aircraft aluminum and also a catalyst for Hydrogen
Embrittlement in high strength aircraft alloys.

Whoa. I had no clue. Can't think of a time I used it on aluminum, but that's not to say that I wouldn't have if I didn't know this.

Great tip.

I really like Superclean. its 7$ a gallon at walmart.

Having done this on both my 914's and 911. The gallon of carb cleaner works the best. My .02c.

It needs to soak.

http://www.summitracing.com/parts/sum-9190...CFQZffgod0j4AOw

Ultrasonic is great. But the cleaner is small if you have bigger parts, this is a good alternative and in the long run cheaper then Brake cleaner or similar...

Thanks, this is working quite well. Does a pretty good job of stripping overspray off fasteners, too.

iv been using kerosene in a spray bottle for that kinda stuff. works nearly as good as carb cleaner