Cleaning Tank Lights

I use vinegar for the same problem. You need to leave it in contact with the limescale for a few minutes, then wipe. For stubborn deposits, soak tissue paper in vinegar, lay it on the limescale for 10 minutes or so. Most of the used tanks I have bought arrived with tubes covered with scale, but I cleaned them all up like this. You might have to take the tubes out, though. A scrub with a pot scourer (plastic, not wire) will get rid of lighter deposits, but don't press too hard or you could get a had full of broken glass.

Just given this a go worked a treat! Thanks for the tip

I only use vinegar - not salt and .................... to spare their feelings.
Seriously, vinegar's  really cheap compared to lemon juice.

Vinegar is also good at cleaning the tank glass (outside obviously) - especially when you have young kids with grubby little mitts! Just need to be careful in the application.