Anyway to clear this!

[VS-S-PACK-UTE]

hey im just wondering if there are any tricks etc that u can use to clear the mouldy looking residue out of the radiator overflow bottle? the shape of the container makes it hard to reach certain areas with a brush etc so i was wondering if there are any chemicals etc that would clear it?

[another old bloke]

Remove the overflow bottle, buy some CLR from the supermarket and it should do the trick, quickly.
A hardware store will have it if the supermarket doesn't.
Hope this helps.