When you forget to wash a paint roller and tray, and they solidify to the point that they are best chucked in the bin, there is a way to bring them back to life.
Run a bath. Enjoy a relaxing soak. Leave the water in when you get out. Add a scoop of washing powder. Swirl. Throw in roller and paint tray. Leave 12 hours.
12 hours later, use an old nail brush to scrub both roller and tray until paint is removed. Run under tap to get rid of the last of the paint.
Empty bath, give it a clean, and voila!