I found a link for an in ground composter that uses a galvanized trash can. It sounds very easy to make and I like that I can bury very close to my kitchen door so it would be convenient to fill with veggie scraps. BUT I am concerned as to whether it would be safe to use compost from galvanized metal in my garden. Not sure if it would have toxic chemicals leaching into the compost. Thanks in advance for any insight that you would have. Here is the link: http://www.vegetablegardener.com/item/8890/diy-food-scrap-digestercomposter
Are you using the compost on things you eat, or on ornamentals? Galvanized metal when it is in contact with moisture (especially if the pH is acidic) can leach metals (primarily zinc which isn't all that harmful at least in small quantities, but could be small amts of other things too). I doubt if it would leach enough stuff to cause problems for the plants themselves, but if you're growing edibles then it's never a bad idea to use something like untreated wood that won't leach anything.
Sorry, I guess I didn't include that I meant to use the compost on my veggie crops.
I know zinc is necessary for good health and the cadmium and chromium are necessary too. I don't think the suggestion in the second link idea to use reclaimed pallets is a very good idea at all! I know pallets are treated with chemicals probably much worse than the zinc of the galvanized metal. And I don't want to use plastic trash cans buried as I'm sure the petrochemicals would be even worse...I'm thinking it would probably be relatively safe for the metal can because the vermicompost that is made within it will be greatly diluted within my much larger garden beds. I was just attracted to the fact that this could make it much more convenient to dump my kitchen scraps closer to the house rather than haul them all the way to the big compost bins.