One of the hazards of DIY is accidental paint spills. Spilling gloss (oil-based) paint on a carpet will almost certainly leave a permanently marked area. However, if you act quickly and don't let the paint set into the carpet, it is possible to minimise the damage. Remember that oil paint and water don't mix, so keep some paint-removing solvent on hand for such emergencies. If your carpet is valuable, it is advisable to contact a professional carpet cleaner immediately when the accident occurs.
Scrape the paint from the carpet. Use any flat tool that you have on hand, such as a paint scraper or spatula, as it is important to work quickly. Be careful not to spread the spill further.
Pour solvent on the spill and press a wad of paper towels down hard. Do not rub. Dispose of the towels and repeat with clean towel. Continue this until you have removed as much of the remaining paint as possible. Use more solvent, if necessary.
Stroke the stain from the outer edge inward using a cotton cloth or towel, dampened with solvent. Do not scrub the paint into the fibres; keep working around the stain, edge to middle, to prevent spreading it.
Fill a bucket with warm water and detergent and gently swab the stain. Use cotton towels to absorb the excess water. Repeat until the solvent is out of the carpet. Remove as much moisture as you can, then allow the carpet to dry naturally.
Establish what sort of paint it is by reading the brush cleaning instructions on the can. Oil-based paints require solvent, while latex paints need soap and water. Tiny surface spatters can be removed easily by wiping with a solvent-dampened cloth. If they are dried, try snipping the fibres with scissors. Remove residual odours of solvent by sprinkling baking soda onto the dry carpet and vacuum.
Caution is required when using solvents, as they are flammable.