Hard water spots -- caused by minerals left behind when water evaporates -- may make your drinking glasses look a little dirty no matter how many times you clean them. Resolve the problem by cleaning the drinkware with a mixture of vinegar and water. Rinse and dry the glasses thoroughly afterwards.
Help for Hard Water Spots
Mix equal parts white vinegar and distilled water in a spray bottle. Tap water may be used in a pinch, but distilled water is free from the minerals that caused the hard water deposits in the first place.
Set the spotted drinking glasses -- whether plastic, acrylic or glass -- atop a folded dishcloth. It doesn't matter whether the glasses are right-side-up or upside-down unless the spots are on the inside. If the spots are on the inside, set the glasses upright or on their sides atop the towel.
Spray the vinegar-and-water mixture over all of the spots on the drinking glasses. Allow it to set for a minute or two.
Spray more of the vinegar mixture onto the sponge side of a nylon scrub sponge. Wipe the spotted areas of each glass with the wet portion of the sponge. If the spots do not come off the glasses, rub them gently with the scrubby side of the scrub sponge. If they still do not come off, wet the sponge with pure white vinegar and wipe down the spots again.
Rinse the glasses inside and out with tap water. Shake out most of the water over the sink; then dry the glassware with an absorbent dish towel.
If you usually wash your drinking glasses in a dishwasher, help prevent water spots by adding 1/4 cup white vinegar to the dishwasher's rinse cycle by placing it in the open compartment in the door before the rinse cycle begins. Prevent water spots by adding the vinegar to the open compartment in the door before washing the glassware, using your regular dishwasher detergent in the detergent chamber that closes.