It is thirty eight years ago since our currency went decimal, also at the same time historic coin slang and nicknames also disappeared. Most coin slang generally was a nationwide thing except of course Cockney and Romany names, and as far as I know there is no local Thanet slang term for coins. "Bob" "Tanner""Florin" we are all familiar with, less familiar is the Threepenny "Joey". The name "Joey" was first used for the small fourpenny piece or groat. This coin was issued on the advice of Joseph Hume MP in 1836, the idea behind the coin was that it would be a handy little coin to pay a short cab fair. The cab drivers hated the coin because most people used pay their fare with a sixpence and let them keep the change as a tip, then in the dark streets the cab drivers would mistake the Joey for a sixpence and give change. They nicknamed them "Joey" and would often spit on them in disgust. In 1845 the silver threepenny piece was reintroduced and this was nicknamed the threepenny "Joey" and the name followed on.
Halfcrowns had exotic names like "tusheroon""tossaroon" or "tosheroon". "Mazda Caroon" is another slang term for the half crown which is a corruption from the Italian mezzo (half) corona (crown). As to whether these slang terms were used locally I do not know. The word "Quid" has been recorded as far back as 1688 and was used by criminals to describe guineas , this in turn passed onto the Sovereign when Guineas ceased being minted in 1813. The term "Nicker" and "Half a Nicker" to describe a pound is a New Zealand term and "Bar" and "Half a Bar" is a Romany term. Ten shilling notes had a cockney term "Gennet". Other names for Sovereigns and Guineas were "Bleeders" "Jemmy O'Goblins""Glisteners""Janes""Harlequins""Megs" and "Yellow Boys".
Most of us are familiar with the racing slang pony (£25),monkey(£500),cow (£1000),plum (£100,000) and a marigold (£1,000,000).
Above is a handful of "Joeys" which can legally be turned in Jewellery. Under the 1971 coinage act section 10 it is illegal to break or melt coins that were legal tender on or after 16th May 1969 without a licence. As the silver "Joey" was demonetised in 1944 there are no restrictions, so that explains why silver "Joeys" are used for bracelets and other Jewellery.