Acrylic paints are a good choice because of the speed of drying and the lack of fumes, and being water-based it is easy to clean up. Even so, care must be taken when disposing of excess paint and rinse water. It is not a good idea to pour solutions of paint down the drain, and that includes street drains and the garden. Acrylic polymers are a kind of plastic and it has been discovered that even tiny particles in water systems end up in the waterways and eventually are carried to the sea.

The solution is to allow all the paint excess to dry. When dry, the paint is stable just as it is on the painting. Any toxic chemicals can only be absorbed when diluted so this works for all acrylic paints. Some like to use brushes to paint and others like pallet knives or even their fingers, but whatever the tools you prefer, it’s a good practice to wipe off the excess as much as possible before rinsing them. This will significantly reduce the amount of paint in the rinse water. You can use paper towels, newspaper or rags.

At the end of a painting session the rinse water can be set aside to settle or for dehydration. You may be able to pour off some water then wipe down the jar with newspaper which will absorb the paint residue allowing it to be thrown in the household rubbish bin.

A tip from a member: To dispose of dirty acrylic water I have a large 5 gallon bucket under my work table and empty dirty water into it. When it gets fairly full I take it outside where I have a large container of playground sand (from the hardware store) in the low bushes, pour the dirty water in and the sand acts like a sieve allowing only clean water to flow through holes I have poked in the bottom. I have not changed the sand in 3 years and kept my sink drains paint free.