
Based on the information provided, particularly the sentiment from the coin collecting community, the strong recommendation is to not clean your 1964 nickel. As noted in the context, experienced collectors are generally against cleaning coins because it can permanently damage the surface, remove the original patina that develops over time, and significantly decrease any potential numismatic value.
A 1964 Jefferson nickel is a very common, modern coin made of a copper-nickel alloy and contains no silver. In most circulated conditions, its value is just its face value of five cents. Because it is not a key-date or rare coin, cleaning it will not result in a major financial loss. However, the practice of cleaning is still discouraged as it can create unnatural toning, micro-scratches, and a polished appearance that is undesirable to collectors.
If your goal is simply to remove loose surface dirt for your own satisfaction, the safest and only recommended method is a gentle rinse. You can run the coin under lukewarm distilled water and then pat it dry with a soft, lint-free cloth. It is crucial to avoid any rubbing or scrubbing. Do not use abrasive cleaners, metal polishes, vinegar, or any other chemical agent, as these will strip the coin's surface and cause irreparable damage. In summary, the professional standard is to leave coins in their original state.


