This article is from the Toyota RAV4 FAQ, by Ralph Becker with numerous contributions by others.
Toyota sells small bottles of touch-up paint. The parts department
can look up the paint code and sell you the correct one. If you
have the paint code, any autobody supply store can make you a
larger amount.
For very small chips you can use medium weight porous paper and
just dab a sharp corner of the paper with a small mound of paint
on it in the chip. For very thin scratches, you can use a thin
paper towel dabbed in paint and then just sort of drag it along
the scratch. For larger scratches, matchsticks or paint brushes
work well. Make sure to have a towel and some paint thinner
handy in case you make a mess.
It is best to apply touch-up paint in many thin layers to fill a
chip, rather than fewer thick layers. Fill the chip until it is
slightly higher than the surrounding body, then use a polishing
compound to equalize the height. Finally, wax the chip and
surrounding area to protect it.
 
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