To clean the pillow using the wet cleaning method you can do the following:
Combine a shampoo for upholstery following the instructions from the manufacturer in a pail. Ensure that the solution or the formulation is ideal for shampooing using the hand or sponge. There are several cleaners or solutions that are concentrated and intended to be used with a machine. Stir the mixture using a sponge to make dense and frothy foam. Squeeze the sponge out and leave it wet but not drenched.
Get an ample amount of foam using the sponge. Put the foam to the pillow by applying it if soft and circular motion. Do this in every crevice of the pillow especially in the piping. Whisk out the surplus foam from the pillow using a clean towel. After all that is done, put it in a clean towel to dry.