This MRAT explains the controls which must be in place when making or using purchased compost in gardening activities.

Cold water dyes and hot water dyes. Dyeing with mordants.

Developing colour or black and white films or prints. Fixing colour or black and white films or prints. Stop baths used between developing and fixing. Chemicals used for specialist treatments.

The corrosion resistance of iron and steel can be improved by treatment with sulfuric and phosphoric acids. Other metals are also affected through the introduction of chemicals.