The use of chemical cleaning agents to improve the flow through the drain from a sink and remove stains from the sink itself; many use strong acids or alkalis, others contain enzymes or hypochlorite.

The use of disinfectants to attempt to destroy microorganisms which may be present on surfaces etc in food technology areas.

A variety of pigments, paints or inks can be used on textiles.

Explains the relative merits of three different ways of producing printed circuit boards by etching copper-clad boards.