You may notice when driving at slow speeds that the front wheels sound like they have tin cans dangling from them. Believe it or not, this is a build up of rust on the back of the brake disc.

Remove the discs and clean off all the loose rust. In the picture below the arrow indicates where this rattling noise comes from.

Clean the centres of the discs...

...and the edges.

You can also take the opportunity to check the discs are not worn by measuring the disc thickness by using a pair of vernier calipers or similar measurement tool.