A Huntingdale collector is offering a $20,000 reward for rare coins valued at $200,000 stolen from his factory last month.
Michael Edwards, the director of Commercial Sewing in Kenwick, says the coins are so rare, the thieves have next to no chance of selling them.
He is hoping the lure of easy money will result in the coin collection being returned to him.
"They're collector's pieces," Mr Edwards said.
"It's not something you could take to Cash Converters - well you could, but it would be an easy way to get prosecuted.
"At Perth Mint, they'd want your licence and passport.
"The reward is $20,000 to the person who hands the coins in, or if the police catch them, I'll donate the $20,000 to either their charity or Princess Margaret Hospital."
The 63-year-old said he had decided to sell the coins about six months ago after an ultimatum from his wife.
"Consequently, I've been advertising the coins on eBay and Gumtree and I've had them in a safe here in the factory," he said.
The collection was stored in a safe which was stolen from the Royal Street factory sometime between Saturday, December 21 and Saturday, December 28.
Mr Edwards believes the robbery was related to a call about one of the online advertisements.