What does "coin collection" mean?

The maintenance of coins is mainly aimed at plum blossom 5 cent coins. Plum blossom is the top grade in the circulation of five cents, which is carefully cleaned and maintained. All stains on the surface of the coin are cleaned without damaging the coin. After machine washing, it takes several maintenance procedures to restore the bright color of copper coins. Anti-oxidation and image curing procedures are also crucial. Product image: no rust, no dirt, no bump, shiny. It will not be oxidized, discolored and rusted within 5 years after being stored in the open air, and the quality will always be as good as new after being packaged and preserved. It is an excellent substitute for new plum blossom products.