In summary, cookie tin cans are not made of 100% tin, but of tinplate. Tinplate combines the anti-corrosion properties of tin and the mechanical strength of iron by coating a layer of tin on the surface of the iron plate, making it an ideal cookie tin can material.

Tin and tin-plated steel are relatively safe under normal use, but when baked at high temperatures, harmful substances may be released, especially when there are coatings or printed patterns in the can, these coatings and inks may decompose and release toxic substances at high temperatures.

Pressing seal is a common sealing method, which is widely used in various packaging containers such as metal cans and plastic cans. The principle is to use mechanical pressure to tightly press the joints of the can body and the lid together to form an effective seal.