Any help? A porcelain sink horrible abused by previous owners. I've tried bleach and later BKF with a drill brush with little improvement. : r/CleaningTips
Can I drill a hole for a faucet in a porcelain sink? - Home Improvement Stack Exchange
Can I drill a hole for a faucet in a porcelain sink? - Home Improvement Stack Exchange
How to Drill a Hole Into a Cast Iron Sink | DoItYourself.com
How to widen a hole in porcelain, ceramic, granite or marble sink.
Making Hole In Ceramic Sink - Kitchen Units & Worktops - BuildHub.org.uk