A detergent is built up from lots of ingredients each of which has a specific job to do – here is how some of these ingredients work.
Bleach
removes coloured stains as well as whitening dingy laundry, but it can treat coloured dyes as if they were
stains so it is best used for whites loads only. 
Surfactants
remove anything greasy from fabrics making them great on stains and food residues. Good detergents have
several kinds of surfactants which attack different stains.
Enzymes
are proteins that are very efficient at breaking down stains and food residues. Each enzyme will remove a
specific stain type and there are several kinds in a biological detergent. Enzyme action can damage wools
and silks so are best avoided for these fabrics.
Not all detergents have all component types which lets them be used for different fabrics and conditions...
Builders
tie up the hard water molecules, softening the water and letting the surfactants get on with removing
stains and food residues. So remember – harder water requires more builder!
Polymers
Specific polymers carry out specific tasks such as keeping soils from redepositing onto clothing in
the wash water after they have been removed.
Perfumes
are specially designed to survive throughout the wash process and to leave a long lasting freshness
on your clothes.
