Do not use Borax, too many impurities.
Use Food Grade Diatomaceous Earth.
See;
https://www.diatomaceousearth.com/
Experience the difference of pure food grade diatomaceous earth!
Safe for human and pet use, our DE is free from all additives, certified organic, professionally packaged, and is the only official diatomaceous earth health supplement on the market.
Food grade DE - meets U.S. Food chemicals codex standards
Omri listed - for organic use
Natural product - safe for human or animal consumption
No additives - 100% pure freshwater diatomaceous earth
No Contaminants - Professionally Packaged Using Stainless Steel Machinery