Garden magnet roller/large magnet (Wellesbourne, CV35)

I'm shovelling and sieving a bunch of old dirt in my garden that the previous owner used as a dumping ground for nails, bolts, screws etc.

Does anyone have a spare magnet roller or fishing magnet that I can borrow to expedite this very tedious process, please?

Because I'm manually sieving it and checking at the moment, and it's a 50m2 plot, which is quite backbreaking 😂

Thanks in advance