Remove any hardware from the toy box.
Sand the entire toy box to remove all the paint. Use a sander with 100 grit sandpaper to sand the large portions of the toy box. You will have to sand small crevices by hand. If you are only painting the outside, you don't need to sand the inside.
Wipe the toy box down with a damp cloth to remove all the dust and dirt.
Pour primer into a paint tray and roll a paint roller through it three to four times so it is completely coated.
Roll the primer over the entire outside (and inside if you prefer). Use a small paintbrush to reach any areas you couldn't with the roller.
Let the primer dry for 10 minutes and then apply a second coat. Allow this coat to dry for an hour.
Mix your paint with a paint stick and pour enough to fill your paint tray two-thirds full.
Paint the toy box in a thin layer of paint. You can use a roller or a paintbrush.
Allow this coat of paint to dry overnight.
Apply a second coat of paint and allow it to dry overnight.
Hand paint or stencil on some of your son's favorite things such as trains, soccer balls, spaceships, pirates, etc. You can also use letter stencils to paint his name or the name of his favorite sports teams or action hero. Tape the stencil down with masking tape so it does not lift up and blur the image. Tape newspaper over the toy box around the stencil to avoid getting paint on the toy box. Spray paint works best for stencils. Hold the spray paint can 6 inches from the toy box and lightly spray the image. Allow it to dry over night and then remove the stencil and newspaper.
Apply your polycrylic protective finish with a paintbrush.
Allow the toy box to dry for 48 hours and then put all the hardware back on and fill it back up with toys.