How To Cash In On Rare Coins - Expert Tips

George Lim began his coin and banknote collection 30 years ago with a single note, the first 10,000 Singapore dollar bill he received. "As soon as I made that amount, I saved it to remember it," says Mr. Lim, a Singaporean real-estate developer, whose collection today includes over 100 rare coins and banknotes.

1910 Yunnan Spring Dollar

Mr. Lim plans to auction 68 coins and notes from his collection in Hong Kong on Aug. 22. He hopes to cash in on growing interest in collectibles from mainland Chinese buyers who've already pushed up the price of rare stamps, wines and art in recent months.

The lots in the Hong Kong auction will focus on Southeast Asian and Chinese coins and banknotes. One item of note is a rare Yunnan Spring dollar dated 1910 with an unusual spelling mistake embossed on the coin. Mr. Lim spoke with Angie Wong in Hong Kong about collecting etiquette and how to safeguard yourself from picking up a fake. The following interview has been edited.

WSJ: What do you look for when starting a collection?

Mr. Lim: Rarity and quality. Quality is basically the condition of the coin, who commissioned the coin and when it was produced. But if the coin is rare, then the wear and tear isn't as important, especially if only one or two survives.

WSJ: Do you think it is good to hoard a collection or sell it?

Mr. Lim: This is only a hobby. There are collectors who keep all the good stuff and leave nothing for others to collect. I think if you are collecting, you must release something from time to time [so other collectors can enjoy them]. I wanted to collect China silver coins, but all the top China silver coins are going into one person's hands. So I had to go for Chinese gold coins instead.

WSJ: How do you know when to sell?

Mr. Lim: Let the market decide the price. Watch the auctions to see what is selling. Also know that auctions goes up and down with the economy.

WSJ: What tips do you have for someone who wants to start collecting?

Mr. Lim: Newcomers, especially those interested in Chinese coin collecting, need a base knowledge. Read lots of books on the topic. Get to know what each coin is about, and the story behind it. Talk to dealers as well.

WSJ: What about forgeries?

Mr. Lim: It is very common for forgeries in China, especially if the coin is worth a lot. The best thing to do is safeguarding yourself by buying coins approved by a recognized third party grading service.