The grouting between the tiles in my shower cubicle is discoloured - and wasn't done very well by the builder when it was installed 10 years ago - so I want to remove and replace it.
I have tried various attachments on a Dremel-type device, without much success. The litttle discs disappear in double quick time - but make little impression on the grouting. However, one slight slip, and they mark the surface of the tiles. A little conical metal thing with bits of diamond on was slightly better - but most of the diamond bits had gone after going round one tile.
So what *does* one use to chop out the old grouting?