You can put a couple drops of dish soap in an once of vinegar and clean your gear. It's not going to hurt them, but they won't look like they came back from the repair shop either. It's a way to make sure no grease or grime builds up. Nothing wrong with cleaning torches if they've been handled with greasy hands. In fact, it's a good idea. If you do this with a little pressure added, you are checking your connections at the same time. Rinse with clear water and dry.
Yup. If you stick to plain old Dawn (not the antibacterial stuff) it is just pure detergent. Nothing in that, that is dangerous in an oxygen environment, so wash away. I try not to touch my torch with greasy hands, but that's not always an option for all.
Doing this with pressure in the torch is an even better idea. Not only is it a leak check, but it also keeps stuff from getting inside. The point is though, don't open up the torch when you're cleaning it. Keep it all together. If you have to clean the inside, take it to a pro, use the proper O2 safe solvents, and do a full rebuild.
Still, you won't get a polished shine from this.
I use Zildjan Cymbal polish on mine and it works great.
This is what scares me. This contains waxes and solvents, and neither are safe on the o-rings or anything exposed to pure O2.
At the very least, be careful where you get this stuff, and do not use it on a disassembled torch.