HPL or high-pressure laminate is a very sturdy material which consists of different layers which are pressed together under a high temperature. As a result, the material is very durable and UV-resistant.
You can use your HPL side tables inside as well as outside.
Dirt does not easily stick to the material, which makes your side tables easy to maintain.
Use a damp cloth and water to clean spilled solutions. The quicker you remove them, the easier.
Use a solution of water and mild soap to clean more stubborn stains.