I just rub them over with a warm soapy cloth.
No, that is not their intended use.
Both
As long as the surface is clean and dull, then either an oil or acrylic primer can be used to cover oil-based paints.
Turpentine is a substance used to thin and clean oil-based paints, made from pine wood.
Over time, oil paints change chemically, so large areas will peel if painted over with fresh oil paint. A base should be used but that would not be conservation but repainting. Hard call.
Oil paints are slow drying paints made from suspending pigments in oil.
yes, you can thin paint to use like stain. just thin with what ever you would clean it with. waterbase paint use water. oil base paints use thinner.
Oil paint, pastels, color woodcuts.
mineral spirits
Alkyd is used to create paints that will dry extremely hard and will resist multiple cleanings. Normally, alkyd paints are oil-based, but there are now water based varieties. You can find alkyd paints on doors and trim both inside and outside houses.
In the past oil paints referred to either petroleum based paints or linseed based paints. Today in the USA petroleum based paints are no longer sold and it is difficult to find linseed based paints though they do exist with a small proportion of linseed oil. Alkyd paints are made with synthetic oil and are readily available and have come to be known as "oil" paint.
paints based on oil