"Dirt, oil or germs from hands can mark up cell phones," Ek explains. "Wipe the screen at least daily with a microfiber cloth." Also, your phone case can trap dirt and grime along the edges.

First, switch off your TV as it’s much easier to see the grime and dirt on a black screen. Some TVs will come with a microfibre cloth included in the box. If it doesn’t, it's worth buying one.

The best and easiest way to clean a television screen is something you probably already have in your kitchen. There is ...