Maybe I'm giving up prematurely but I've tried several tips. Plus some of our grout is falling apart.
Thus I've taken on the uneviable project of removing all the grout in our shower tile floor.
What's the best grout removal tool for this job?
An oscillating multi tool and a rectangular grout removal tool will help you remove grout lines without losing your cool (or hair, unless you're already bald-sorry).
Here are some tips
-Apply two layers of duct tape along surfaces you don't want to scratch with the tools
-Use a grout attachment with the oscillating tool