Hard Water Stains Here’s how you make it: Fill about half a spray bottle with distilled white vinegar. Add in 1/4 cup of lemon juice. Fill the majority of the remaining space in your spray bottle with the dish soap of your choice. Shake the bottle to mix together ingredients. Use your solution on hard water stains! Spray it on liberally and let it sit for 30 minutes. Then scrub away the grime. Rinse, dry, and marvel at the glorious results.