Many items don't require any special preparation other than packing securely and finding a large enough box which is why having a good taping machine is necessary. In general, you'll need to drain all the fluids from an item before packing. After you've finished, seal the item in a plastic bag to prevent any residue from leaking out and weakening the container. If the item contains a hazardous substance that can't be removed, be sure to note this on the shipping paperwork. You may also need to affix hazardous material stickers on the outside of your package.
Different carriers have different guidelines for packing and shipping hazardous materials.
For large, bulky items, use a sturdy corrugated cardboard box sealed using a taping machine. Consider double-boxing the item if it's heavy and/or delicate. For car hoods, doors and other oddly sized parts, ask local auto body shops if they have any boxes that will fit the item. Just make sure it's still sturdy enough to properly protect the contents.
Tires should be shipped in individual boxes. Protect the wheels by covering them with a non-abrasive cloth (to prevent scratches), then cardboard. Use tie down straps to hold the cardboard in place. Five-foot-tall wardrobe boxes are great for shipping oversized items; use a good taping machine to properly and securely seal the boxes.
For large, heavy and dirty items like transmissions, place the item inside a large plastic storage tote that's been padded with dense foam. Packing peanuts or bubble wraps are fine for lightweight items but not recommended for heavier parts. Seal the tote securely by wrapping heavy-duty strapping tape completely around it in both directions, then place inside a snug-fitting cardboard box sealed using a taping machine.
