Ask the moderator Ed Buffaloe about "solarisation". He has a web-site (I don't have the address) where he describes it. It's done at the printing stage and includes flashing the print after it has been put into the developer.(posted 8592 days ago)Also, ordinary developing with very hard paper, and hard, direct light during the photo-session, will give a silvery look.
I don't know about any toner that gives a silvery look, but then I don't know that much about toning (I only use selenium toning).