CAUTION: Some of these materials are toxic in their dry unfired or fired state. You should always use a dust mask when working with these materials. We have an inexpensive, Toxic Dust Mask available. Also Material Safety Data Sheets are available on request or can be downloaded from MSDS Search. These materials have always been potentially harmful, so let’s get serious about safe handling. gerbor-gum Grog, Mulcoa 20 - 1 pound grog-1$1.70 Gerstley Borate - 5 pounds gerbor-5$4.55 Grog - 5 pounds grog-5$2.75 Gerstley Borate - 10 pounds gerbor-10$8.60 Grog - 10 pounds grog-10$5.30 Gerstley Borate - 25 pounds gerbor-25$20.50 Grog - 25 pounds grog-25$12.75 Gerstley Borate - 50 pounds gerbor-50$39.00 Grog - 50 pounds grog-50$24.50 Gerstley Borate - 100 pounds gerbor-100$74.00 Grog - 100 pounds grog-100$41.00 Grog - 500 pounds grog-500$220.00