If you have leather stamps to sell that have a bit of rust on them, take a hint from Ron Ross at the International Internet Leathercrafter's Guild.

Note - this is generally for chrome-plated tools only!  This mixture will corrode steel tools.  It may be used on them but try it first with a "junker" first!   

1.  Disolve a teaspoon or two of cream of tarter in water in an ALUMINUM pan and heat on stove until simmering.   Cream of tarter is found in the baking dept at the grocery store.  Do not use a steel or iron pan as it will react with this mixture.

2.  Remove excessive rust with super-fine steel wool ( 00 or 000 ) if called for.  Submerge tools in pan and let them simmer awhile.  Stir lightly from time to time and check for progress.  You will see the water become cloudy as the rust is removed.   

3.  Check for progress from time to time and remove tools when satisfied.  CAREFUL! Tools will be hot.  Wipe residue off with fine steel wool or with Scotch-Brite pad.  Rinse tools well in water and dry completely.  A hair blower works great for this.   

4.  If you live in a high moisture area you may want to prevent future rusting.  A very light coating of any of the commercial plastic spray coatings will work.  I myself use Rain-X which is a micro-crystaline wax that can be found in the auto dept at stores.  Just coat and buff; this will leave a fine layer of wax which will retard further rusting.