if they have tyres on then just whack them in a bin liner with plenty of tape, if no tyres, wrap them alot, I used tnt to get some alloys without tyres and he advised me not to send them as if they were damaged in transit then no damages would be paid for, so I wrapped them up in recycling bags with handles (probably only have them down here) and stuffed newspaper in every place i could find and tape them up.