F style oblong metal tin cans have good ductility and are called "sounding tin" because of the twisted sound. The crafts will be deformed after being twisted, so this method cannot be used when purchasing, but we can “smell the sound” by simpler method: use the nails to gently sweep the tin from the palm of the hand, 97% of the tin has clear metal Sound and short echo; 99.9% of the tin sound is not crisp and no echo, it is a superior tin.
The tin of the F style oblong metal tin can itself is a precious metal, and each finished product should have its value. Pure tin, color like silver, bright as a mirror! The tin content of 97% after polishing is not bright, it is dark and bright; the content of 99.9% of the tin is polished and bright silver, which is a superior tin, looks like silver.
The quality of the F style oblong metal tin can mainly refers to the purity of the tin when it is used. The higher the purity of the tin, the more durable it is. The food is not only harmless, but also can be kept for a long time; the tinware with low purity and the food It is easy to deteriorate and not durable enough. Imported tinware is mostly marked with purity, most of the domestic tinware is not specified, but we can know a little from its origin.