Use a plastic paint scraper to remove the paste and loosened ... A fairly new rust stain may succumb to the mild acid of white vinegar. Pour the vinegar over the stain, let sit for 10 minutes ...
To remove hard water stains: White vinegar and Baking soda is the cleaning method I prefer to use ... It has Hydrocloric Acid, kills 99.9% of household bacteria, and removes rust, lime scale & hard ...