How to clean paint brushes: acrylic and oil paint

The two paints need opposite treatment. Acrylic is water-based while wet but dries to a plastic that water can't remove, so speed matters. Oil paint doesn't mix with water, so it has to be loosened first, and its rags and solvents need care.

Acrylic or oil: the differences

Acrylic brushes

1. Don't let the paint dry in the brush.

   

   Wash brushes as soon as you finish. If you can't, keep them in water while you paint (W&N).

   You should see: paint still wet and soft in the bristles when you start cleaning.

2. Wipe, rinse, then wash with mild soap in your palm.

   

   Wipe the brush on a lint-free rag and rinse it under running water. Then wash it in cool water with mild soap, swirling the soapy brush gently in the palm of your hand (W&N).

   Rinse well, especially at the base of the hairs where paint collects, and repeat until the water runs clear (W&N).

   You should see: rinse water running clear, with no colour coming from the base of the hairs.

3. Reshape the head and dry the brush head-up.

   

   Squeeze out the water, shape the head back to a point or edge with your fingers, dry the handle and the metal ferrule, and stand the brush head-up until it's fully dry (W&N).

   You should see: no colour coming out when you press the damp brush on a white tissue, and a neat point or edge.

Oil paint brushes

1. Careful: put the used rag straight into a lidded metal bin: rags with oil on them can catch fire as they dry (W&N).

   Wipe off as much paint as you can on a rag.

   

   Wipe the brush firmly on a rag (W&N). A little cooking oil worked into the bristles helps release more paint into the rag (W&N).

   You should see: most of the colour on the rag, and only a little left in the bristles.

2. Wash it on a bar of soap until the lather is clean.

   

   Push the brush into a bar of soap with a circular movement, then rinse, and repeat until the lather is clean (W&N).

   Winsor & Newton also sells a brush cleaner that it says is far less toxic than solvents and biodegradable; that's the maker's own claim.

   You should see: white lather with no colour in it.

3. Let it air-dry, or keep it wet for tomorrow.

   

   Let the brush air-dry before you use it again (W&N).

   Painting again the next day? Wrap the brushes in a damp cloth inside a plastic bag, or stand them in a jar of water; oil and water don't mix, so the paint stays workable (W&N).

   You should see: a dry brush ready for next time, or brushes wrapped or standing in water overnight.

What to do with the dirty water and solvent

• Acrylic rinse water: collect it in an open container and let the solids sink. Pour the clear water down the drain and put the solids in household waste, or as your council's rules say (Schmincke).
• Solvent: keep it in a sealable jar. When the pigment has settled, pour the clear solvent into a second jar to reuse (Schmincke, W&N). Take the wet sludge to a local waste site (Schmincke). Nothing goes down the sink (W&N).
• Oily rags: always into a closed metal container (W&N).

If it goes wrong

Mixing next? See how to mix colours from the three primaries.