Parts

Well, first you will need to find a replacement part. If you were on Homeworld, I would tell you to visit the body banks.  Unfortunately, that won't help you.

You can go and find parts for Micronauts on Ebay, or some of the other online auctions. You may be able to find some damaged toys to use for parts at flea markets, garage sales, antique stores, collectible stores.

Many of the Micronaut Collectors on Micropolia Embassy Suite mailing list trade regularly. Perhaps one of them can help you with parts.

Some people have been know to cast damaged parts. Of course, the casting may not produce a good quality piece.  If you know a customizer that makes molds and casts you may want to contact them and ask them to help you. or go to the customizing section and learn how to cast parts yourself.

Even though, this will not produce a "Standard" Mirconaut/Microman figure, some customizers have used "Corps" figures for various parts on their Micros. These figures are cheap and easy to locate at most toy stores.