You can check out http://www.cwc.org/gl_bp/gbp3-0401.htm for information to start.You might also try http://www.glass-fusing-made-easy.com/bottle-glass.html for general info.
Are you recycling bottles and the like or are you recycling art glass?
If you’re going to slump bottles, there was an earlier thread devoted to that topic.
I can tell you my experience. For bottles I turn them into frit and cast them in my own molds. I keep like colors together (which limts the color range) and keep bottles from the same case together.
I only put one kind of glass in my kiln at a time. I’ve found that I need to use a higher temperature range for the bottles to completely melt them. Shards of bottle glass generally require a devitrification spray. (There’s a recipe on this site under “Learn” for the devit spray.)
If you are thinking of using broken bits and pieces of bottle or window glass, keep in mind that the age of the glass might work against you. Old windows and broken bottles can contain lead, or produce carbon monoxide, nitrogen oxides, metal oxides and other gases which can be highly toxic. Ventilate your area well.
If you’re looking to fuse scrap art glass (so called non-fusible stained glass), keep in mind that it’s best to fuse glass from the same sheet to itself. The COEs on that glass can vary widely and without testing, it may be hazardous to your work. (There’s a thread about that here, too.) Some of those glasses require devitrification spray, too.