Re-silvering polish

[Showtime]

Can't find my old bottle, does anyone know brand name/where to purchase please?

if you mean a product to somehow replaces/thicken silver layer, I don't know.

if you mean a good substance to clean silver items - use the cheapest toothpaste!
anything that can be immersed in water from cutlery to jewellery to candlesticks and coins, just smear a thin layer toothpaste on the object, let is work for say 30 mins, then rub with a cloth, rinse & dry.
if oxidization made grooves, patterns and dents really black use a toothbrush (even electric) to get rid of it

Goddard's Silver Dip... is I think what you are after :)