Gold and silver collectible coins issued by the National Bank of Kazakhstan made by a special technology of "proof" quality. Proof quality is the highest standard of coins distinguished by the smooth mirror surface and evenly frosted relief design of the coins.
Precious metals coins must be stored in conditions preventing them from mechanical damage. The recommended storage temperature for coins is from 5 ° C to 40 ° C. It is necessary to avoid influence of the fast-changing temperatures on coins with jewel inserts.
It is not recommended to store collectible precious metals coins in following conditions:
- Without its original packaging – a hard transparent capsule which is designed to protect the coins from fingerprints, dust and foreign debris that can damage the mirror-like surface of "proof";
- Near household chemicals, cosmetics, medicines. It is especially dangerous to store coins next to the chlorine, mercury, and iodine, since coins might be covered with stains or dark patina.
- In polyvinyl chloride albums (colorless, transparent plastic, thermoplastic polymer), as over time, PVC breaks down, releasing organochlorine compounds which can cause greenish patina on the coins;
- Near banknotes, because of possible content of sulfur compounds in paper, this may cause browning of the surface of the coins;
In case of necessity to take out coins from the protective capsule, better to do it in special cotton gloves or special tweezers with soft tips only. At the same time, it is not recommended to clean proof coins by yourself.
Bullion coins of precious metals are produced without the use of proof technology. Depending on storage conditions, stains can appear on bullion coins, representing the oxides of metals and microscopic particles of various substances that fall on the surface of the coins. Having these stains on coins does not characterize them as defective. In case of stains on the bullion coins, they can be removed by using special cotton cloths for polishing silver.
When buying coins at the branches of the National Bank of the Republic of Kazakhstan it is recommended to carefully examine the coins and make sure that the packaging is intact and that there are no visible defects before signing the check control.
Single defects visible to the naked eye that are not deteriorating the appearance, insignificant bevels and burrs on the edging of coin are acceptable.
In the case of detection of manufacturing defects after some time, please contact the Kazakhstan Mint of the National Bank of the Republic of Kazakhstan: Republic of Kazakhstan, Ust-Kamenogorsk, 102/1 Abay Ave., F00K8B3, tel.: 7 (7232) 75 33 50, email: firstname.lastname@example.org
Note: in case of taking out coins from the protective capsules by customers, the claims and objections to the quality of the coins will not be considered by the mint.