Stain on the leather and vinyl upholstery or fabric inside your car can be tricky to remove. Due to the variations of dye used by each manufacturer, it is important to test each of these methods on a small area underneath the
seat to make sure it is not going to affect and alter the colour of the dye.
In case of simple stains, a bit of toothpaste can come handy. For surface stains, nothing beats toothpaste on either leather or vinyl surfaces. Apply a small dab of toothpaste on the stain and use an old toothbrush to gently rub the toothpaste into the area until the stain is removed. When finished, remove excess with a damp towel and allow the area to dry. If the stain is not removed, it is probably embedded into the dye and you'll need a slightly more heavy-duty method, such as the two given below.
When it comes to leather and vinyl, isopropyl alcohol can sometimes help release a stain embedded in the dye. You will definitely want to test a small area first to see how your dye reacts to the alcohol. Many dyes can be easily wiped away or discoloured with too much alcohol, which is why you never want to soak the area, but rather dab it gently. If the stain has been resistant to both the methods discussed so far, it is going to require some gentle soaking in order to release the stain.
If the above does not help, go for a mixture of made from cream of tartar and lemon juice. Mix equal parts of cream of tartar and lemon juice. After testing on an inconspicuous area, apply the mixture to the stain and allow to settle for ten minutes. Then gently wipe the excess mixture with a damp cloth. Check to see if the stain has become lighter in color, or if you're really lucky, disappeared completely. Repeat until desired outcome is attained and then wipe the entire area with a damp cloth and allowing it to dry.
It has to be noted that professional leather experts often claim that many store purchased cleaners, protectants and waxes actually do more harm than good on natural leather. A very gentle leather soap, but not a saddle soap, is all you should need for general maintenance and cleaning. While various products will tell you leather needs special oils and waxes to maintain its condition, in truth, most natural leathers need only be wiped with a damp cloth from time to time to maintain their moisture and softness.