Hi
I've been using clean + easy since 1989 and have used all their different heater styles.
To stop the little dribbles of wax going down the side of the cartridge and therefore making the metal heating plates sticky, you need to wipe the sides of the roller head round with the C+E 'after wax remover' after each client.
At the end of the day wipe over the metal plates, cartridges and roller heads with the remover. Refill with new wax as required.
The remover is oily so this leaves a film on the surfaces so that the next time you clean up any wax lifts off easily.
I think that makes sense!