a buddy just told me they are using this same product in place of sand for blasting paint off.. seems the sand dust is carcinigenic and the shells work GREAT
Ive heard that you have to be aware of any allergies if you use this as a blasting media.... IMHO some of the problems using sand are abrasion and you can stretch the metal and cause wrinkles, the walnut is softer and less likely to cause problems. Someone better versed in metal prep and repair could add lots of better info.