I use Sodium Hydroxide myself
Here is a video on how to make Sodium Hydroxide, you have to be very careful and remember to do this in a well ventilated area, or in a fume home preferably because it does produce some Chlorine Gas.
[youtube]http://www.youtube.com/watch?v=nue1ZGSleEo[/youtube]
When you are mixing Sodium Hydroxide you should treat it as you would acids, never add water to Sodium Hydroxide, but rather small amounts of Sodium Hydroxide to water until you reach the desired concentration.
Heat is a by product of the reaction of Sodium Hydroxide with water, so it should be done in a container that can withstand the heat. Tempered glass, crockery that doesn't have a glaze that will dissolve, a plastic container that can withstand heat and isn't attacked by the Lye.
The reaction will give off some gases that can burn the inside of your lungs, you don't want to breath this in, so again, do this in a well vented area (outside) or under a fume hood.
Sodium Hydroxide will burn the skin similar to acids, in it's dry and wet forms. Treat this like Sulfuric Acid! However, it's a base and not an acid, if you need to neutralize it, if you spill or get it on your skin, you should do so with an acid such as vinegar or even citrus juice. I keep a plastic gallon jug of vinegar close at hand when dealing with Lye or Sodium Hydroxide. If for some strange reason you ingest it, you can drink milk, or if you get it in your eye, milk would be a better choice than vinegar.
Keep in mind that after you are finished, you are probably going to want to store the lye for later use, it would be better if you processed your material in the same container you plan to store it in. Also it's best if the container can stay stationary instead of being moved around to prevent accidents. Make sure you have a safety vent, but you should store the dry and wet versions in a dry place. Sodium Hydroxide and/or lye love water just like Sulfuric Acid does, and will react with any moisture that is in the air.
I have been using lye to remove all kinds of material besides soldering masks, it works wonderful so long as you respect it in the same way you might Sulfuric Acid.
If I missed any of the safety issues, please add
Scott