Perhaps the cardinal rule for pre-pro shot glass collectors is that the glasses should be handled as little as possible, because repeated washing and wiping causes the labels to slowly disappear, along with your pride in the collection.  Dusting is also a no-no and over-zealous housekeepers with dust rags can wreak havoc with a shot-glass collection.  Having said that, however, glasses that have been hunted down in the wild or even on the web typically are cloudy from years of repeated handling by grubby fingers and they've usually often also suffered the insult of having a price tag attached.  Many may also contain mysterious deposits.  Thus, a collector's first impulse is to give them a good wash and restore them to as near perfect a condition as possible.  Here are some guidelines on how to do that without inflicting further damage:

Removing dirt and grease (thanks to Bill Armstrong for contributing this section): Always use the mildest soap possible.  Use your fingers to lather the soap (I use just a dash a liquid dish soap; Ed), no sponges, wash cloths,  or pads of any kind since these tend to trap minute sand and grit particles which will scratch the glass.  

When washing your glass, place a very thick, folded towel in the bottom of your sink.  Run cold water at a medium trickle before picking up your glass. Have your glass already LAYING on your towel in the sink. Hold the glass close to the bottom and not close to the spigot.  When washing with your fingers, do not use any "cleaners" of any kind, since they usually contain grit or strong chemicals which will harm the glass or label, I give the glass a final rinse in a bath of distilled water.  

Dry the glass with a THIN 100% cotton hand towel.  Buy a set of towels just for this purpose only, do not use the towels for anything else (retailers such as The Home Depot sell packs of white, lint-free, cotton "Glass Towels" in their cleaning supplies section; Ed).  Wash your new towels to break them in before using them to dry your glass.  NEVER dry the label of your glass by rubbing them; I pat them dry then blow lightly by mouth.  This works well and you'll see the label dry right before your eyes.  I don't think it's a good idea to let the glass air dry on a rack since that leaves water spots and unseen deposits on glass and label, and worse, they could get knocked over and break (a sin).  Store your GLASS towels where no one else will use them.  

Finally, once  cleaned, I do not handle them, since this leaves finger prints and skin oils on the glass. If you must handle them, use one of your dry GLASS towels; try not to put finger prints/skin oils on the glass, especially the gold bands and labels.  Remember- the serious collector just wants to look at them, so - DO NOT TOUCH.

Removing stubborn deposits:
Here are some ideas for getting rid of deposits that mild soap and water treatment alone will not remove.  I can't testify to their efficacy personally but some collectors swear by them.

Suggestions Welcomed 

glassmaster@pre-pro.com