In my dustless blaster, I used crushed glass; it's about $10 a bag at Northern tool. When I ran out, I used playground sand; no problem with silica dust because it was wet and not floating around in the air. Right now, I have black beauty in my big cabinet. The guy who bought my Dustless Blaster is using coal slag. He did the fenders and inner fenders for my 61 and they came out fine. I also have a HF 110 lb. pressure pot and used it for years with no problem until I got scared of silicosis. I may dig it back out and use glass or coal slag.
Smaller parts that I want to be careful with, I just take to work and use the soda blast cabinet.