However, these are more difficult to search for since they must be entered exactly as printed. For privacy reasons, Huzizit does not allow wildcard searches. The ID should be engraved on the frame or chassis of equipment where it cannot be removed, and where it is protected from normal wear. Often, adjacent to the manufacturers serial number is a good location, since professional recovery agents may look there. If possible, IDs should be engraved on a steel frame.
Techniques exist to recover erased serial numbers using acid or magnetic methods.
Methods are being developed, however, to recover engraved numbers from plastic material. Receipts or other proof of ownership are still required. If you are buying an item secondhand, and it has a Huzizit number which is registered to someone other than the seller, you should ask to see proof of ownership. Huzizit to re-register the item. However, this is recommended only for low value items such as books.