The following post is from The Happy Slobs Guide to Housekeeping

We have very hard water in these parts, which means that every time we use the dishwasher it seems to leave a filmy mess behind. This is particularly true when using the dishwasher to wash anything glass – drinking glasses, glass bowls, glass dinnerware, etc.

I have two tips to share with you on how to remove (or prevent) hard water build up from occuring on your dishes that are washed in the dishwasher:

1)Add a generous glug of vinegar (plain old white distilled vinegar works just fine) to the dishwasher cycle once the water is beginning to fill in the appliance. I’ve found that doing this every time I run the dishwasher makes for a huge improvement in removing the hard water stains and build up.

2)When you notice that certain dishes are getting very bad – almost etched looking, or entirely filmy in appearance – then it’s time to (gasp!) get out your dishcloth and wash those dishes by hand. You’ll only need to do this once in a while, but again – add a very generous amount of vinegar to the dishwashing water, along with a good squirt of liquid dish soap. The vinegar seems to nearly eat away at the worst of the hard water stains left behind. Let air dry, or dry with a clean lint free towel. (I love linen towels for drying dishes, or else flour sack towels which are nearly as good.)

If the dishes are in fact etched, there’s nothing you can do to remove the etchings – since that’s actually tiny little scratches imbedded in the glass. But, if you have hard water and find that getting your glasses sparkling clean is a real chore, then try the vinegar tricks listed above and I think you’ll see a big difference.