Wear safety glasses, gloves, and a dust mask
Clear the area and protect nearby surfaces
Use a grout saw, utility knife, oscillating tool, or rotary tool with a grout removal blade
Score the grout line carefully
Work along the grout joint in short passes
Remove grout to about two-thirds of the tile depth
Vacuum or brush away loose debris as you work
Avoid pressing hard against tile edges
Use a scraper or chisel for stubborn sections
Dampen the area lightly to reduce dust if appropriate
Clean out remaining dust from the joints
Inspect for leftover grout before regrouting
Dispose of debris safely