Muriatic acid is best for removing stubborn toilet bowl stains - silive.com
Ring King Toilet Ring Remover, NatureTek Toilet Bowl Cleaner, Multi-Surface Calcium, Water Scale, Rust, Red clay, and Lime stain remover, Fast Acting No Scrubbing 32 Fl Oz (Pack of 1)
Shop Product-TOILET BOWL CLEANER - 1L (32 oz) bottle PART NO 99520 | CaptainPhab
Brillo Sno Bol 24 oz. Liquid Toilet Bowl Cleaner Extra Strength (Case of 12) 32424 - The Home Depot
Zep Zep Winter Green Scent Gel-Based Acidic Toilet Bowl Cleaner | The Home Depot Canada
Zep Commercial 1046423 Acidic Toilet Bowl Cleaner, 32 oz Bottle : Amazon.ca: Health & Personal Care