Dremel Steel 1/8-in Grout Removal Bit Accessory in the Rotary Tool Bits & Wheels department at Lowes.com
Goldblatt Grout Removal Tool with Replacement Carbide Tip - Professional Grout Cleaner, Caulking Remover, Scraper with Soft-Grip Handle, for Cleaning Floor Ceramic Tile Gaps, Tile Joints or Corners: Amazon.com: Tools & Home