All you need to clean anything should be within a topic below:
Dry cleaning is a process of washing garments and fabrics without using water as the washing medium.
Most modern dry cleaners use perchloroethylene but more are beginning to use hydrocarbon solvents (introduced to replace the "F" clean solvent) which is a white spirit cleaning agent that has a much milder action. There are also Cyclosiloxanes that have very low solvency levels and are therefore milder on garments. This makes them safer on beaded fabrics or those likely to run colour, but less good at removing stains and general soiling.
The liquid in cleaning, be it water or solvent, is used as a carrier for dirt and grime. The aim is to suspend the particles of dirt in the liquid and carry this off either to recycle or drain away without re-depositing dirt back on the garments.
No! very few stains are naturally removed during dry cleaning, even though a powerful soap is added to the wash.
Cleaners use "Reagents" to actually react with different types of stains. Some reagents cover wide groups of stains whereas others are very specific and react only with one type of stain.
In reality it's nice to be told what the stains are, so if you know what's been spilled don't keep it a secret. However, lots of stains aren't seen by the wearer and the cleaner uses experience and common sense to guess what the stains may be. Even then it may take three or four cleans before the cleaner gets it right and removes the stain.
This very much depends on how dirty a garment is together with it's colour and fabric content. A cleaner will divide loads up the same way as you should for washing, so if you're lucky and right load is being put into the machine it may take only 45 minutes. If dirty or the wrong type it may take a few hours or days to achieve best results.
The most common reasons are: A reaction to stain treatment.
This can happen in the cleaning machine because of dirty solvent, too much water addition or excessive static. It can also occur because the effect of optical brighteners, added to fabrics to reflect ultra violet light back as visible light, is diminished making the garment appear duller.