First, I would advise never clean your own rugs. Why? Because many are hand made and come from parts of the world where basic methods are used and colour run and the use of plant based fibers that will shrink and discolor if not cleaned the right way.
Having said that most fitted carpets will be fine to clean apart from Sisal, this is because its plant based (cellulose) and presents many problems if you don't clean it the right way, many professionals will not clean it so that just shows you the damages.
Over wetting any carpet can cause the two most known about problems, shrinkage, and browning. They both happen when water get to the backing. A wet carpet dries from the bottom up, most carpets have jute in the backing. It releases its colour and comes to the top leaving a brown, yellowish stain. Shrinkage happens when the water get to the backing and when it starts to dry its will cause some carpets backing to become tight and pull away from the gripper holding it.
So if you carpet is really dirty then it would make sense just to cove over it let it dry then keep doing this until it's clean. It's natural to keep going over and over it when it's dirty but you will pay the price if you do.
Before you start to clean your carpet make sure that it's on the gripper that holds it in place. Many people pull up carpets around the edge to paint the based board or skirting. When you do this you release the tension that the fitter puts into the carpet. This tension will prevent the carpet from becoming creased up and looking like the sea at the beach.
If you have any metal items in the rooms like tables and light stands remove these until the carpet is dry. If you put them on damp carpet you will get rust marks that will only be removed by professional help.
Any wood items sofa legs, table, chairs, etc, that have any type of stain coloring put silver paper under them. The damp carpet will suck up the moisture and release that coloring back on the carpet damaging it.
Ian Harper owns and operates a carpet cleaning company, Carpet Cleaning Network which specialises in the Bio and Eco friendly cleaning of carpets, and soft furnishings, using the most up-to-date efficient methods