Ten-yen coins are made of bronze, and as such, when immersed in Worcestershire sauce, vinegar, soy sauce, lemon juice, or even detergent, the metal oxide and dirt on the surface is eluted or dissolved, and the coins look shiny as though they had never been used.
青銅で造られた十円硬貨は、ソース(調味料)、酢、醤油、レモン汁、洗剤等に浸すと、表面の金属酸化物や汚れが溶出したり脱落して一見未使用硬貨のような光沢を放つ。