"Velvet is woven on a special loom that weaves two thicknesses of the material at the same time. The two pieces are then cut apart to create the pile effect, and the two lengths of fabric are wound on separate take-up rolls. This complicated process meant that velvet was expensive to make before industrial power looms became available, and well-made velvet remains a fairly costly fabric. Velvet is difficult to clean because of its pile, but modern dry cleaning methods make cleaning more feasible."- Wikipedia
Velvet can be very tricky to wash. Silk or cotton velvet can easily become warped when it touches water. They are recommended to be dry cleaned only in order to maintain the best appearance, but for small stains I recommend the following instructions...
Moisten a cloth with warm water (you don't want it to be dripping) and rub gently over the stain in an up-and-down motion. If you rub it too hard you can damage the fabric. For persistent stains mix up warm soapy water, apply the lather to the velvet and dab until the stain disappears. Only attempt to remove the stain 2 or 3 times to avoid any damage. After rubbing the stain use a paper towel to gently soak up the water from the velvet.
If the stain is still visible then it must be taken to a dry cleaner. Whatever you do, DO NOT put your velvet in the washing machine as it will destroy the delicate fabric and the shape will be ruined.
The pile on the velvet can also become crushed which gives the effect of certain areas being lighter or darker in shade. Gentle steaming or brushing in the direction of the pile will help keep the shades even.
If taken care of correctly your velvet cushions will last for many many years! :-)