Cleaning Agents or Chemicals
Oil-based stains: Poultice with baking soda and water OR one of the powdered poultice materials and mineral spirits.
Organic Stains: Poultice with one of the powdered poultice materials and 12% hydrogen peroxide solution (hair bleaching strength) OR use acetone instead of the hydrogen peroxide.
Iron Stains: Poultice with diatomaceous earth and a commercially available rust remover. Rust stains are particularly difficult to remove.
Copper Stains: Poultice with one of the powdered poultice materials and ammonia. These stains are difficult to remove.
Biological Stains: Poultice with one of the poultice materials and diluted ammonia OR bleach OR hydrogen peroxide. DO NOT MIX BLEACH AND AMMONIA! THIS COMBINATION CREATES A LETHAL AND TOXIC GAS!