I have a smaller one from Harbor Freight that I use for a number of things - clean pen bodies after turning to remove any particles from inside them, clean dried nibs, etc. For most stuff, I just use warm water with a couple drops of Dawn dish detergent. Just be careful with the temps of the solution - it gets warmer as it runs due to the movement of the solution.
I also rebuild vintage pinball machines where I use the cleaner LOTS. Metal hardware, plastic playfield parts, balls, most anything plastic except for the decaled parts goes into it. For this type of cleaning, I use Mean Green and warm water - typically 1 part detergent and 3 parts medium warm water. You can't believe how dirty these things get - especially the older machines covered in nicotine resin (would stop anyone from smoking!). I also follow the metal parts up with a tumble in a vibrating tumbler with ground corn cobs.
I'm playing with the tumbler for matt surfaces on pen bodies - just need some more time to get back to it!
Kevin