Foams:
This is a variation of 'Shampoo'. Foam is
generally applied onto the carpet, usually from aerosol
containers, and rubbed in with a dry sponge. Once dry, the
residue containing suspended soil is simple vacuumed away. Since
foam uses little water, there is no danger of overwetting and
the connected complications. But due to the same reason, this
method is not as effective as the "wetter"
methods!
TIP: Some
foams may leave a residue that is difficult to remove and may
cause problems with subsequent wet cleaning.