School paint on clothes: water-based vs oil paint

How to distinguish water-based paint from oil paint

The most important distinction before acting is to identify the type of paint. The most common school paints are:

• Watercolors and acrylics: water-based base. They dissolve with water while they are fresh. They are the easiest to remove.
• Acrylic paints: water-based base when they are fresh, but when they dry they form a plastic film that no longer dissolves with water. They require immediate treatment when they are wet.
• Oil paints: oil base of linseed. They do not dissolve with water at any time. They require solvents.
• School finger paints: usually water-based and washable formula, the easiest to remove.

If you don't know what type it is: touch the dry stain. If it is flexible and can be peeled off, it is acrylic paint. If it remains sticky and oily days later, it is oil paint. If it is rigid and brittle, it could be dry tempera.

Pintura al agua (tempera, acuarela, pintura de dedos): método

The advantage of water-based paints is that, while they are fresh, they can be washed with water and soap without complications:

1. If the paint is fresh, rinse immediately under cold water from the back of the fabric to push the paint out.
2. Apply a drop of concentrated dish soap directly on the area and gently rub with your fingers for 30-60 seconds.
3. Rinse with cold water and check if there is any residual stain.
4. If there is pigment left, repeat and then wash in the washing machine at 3,0-40 °C according to the fabric.

For dry tempera: moisten the area well with warm water to rehydrate it. When it returns to a soft state, gently scrape off the excess with the edge of a card or plastic spatula. Then apply dish soap and wash. School temperas are formulated to be washable in most cases.

Acrylic paint: the urgency of time

Acrylic paint is a plastic polymer in aqueous suspension. When it is fresh, it behaves like water-based paint and can be easily washed. But when dry, the polymers fuse and form a plastic film that can no longer be dissolved with water: only with specific solvents.

That is why with acrylic paint, time is critical. If it is still wet: act exactly the same as with tempera, cold water immediately. If it is already dry:

1. Gently scrape off the solid excess with a plastic spatula.
2. Apply 90% isopropyl alcohol or acetone (on fabrics that allow it, not on acetate or polyester) with a clean cloth, dabbing over the dry paint. The plastic film will soften.
3. When the paint is soft, scrape it with a plastic spatula and remove it with a cloth.
4. Wash the garment in the washing machine to remove residue of solvent.