Stained glass can be easily cleaned with normal glass cleaner or rubbing alcohol (our studio preference). The only specific concern for our glass is to take care around the edges - in places where the solder may be thinner, there is a risk of pulling back the solder from the edge. Try not to do that.
Also, our solder does have a small amount of lead in it, and it's probably best if you wash your hands after handling the glass before eating or preparing food. Again, it is a small amount and far less than would be found in a typical stained glass window (or many other household items for that matter) and is only even slightly potentially harmful through ingestion.