Multi-select problem: How does the next paragraph end?

How to clean quarters
Make sure your quarter is not valued by collectors.
This is especially important if you plan on selling or trading your quarter later. Many collectors find tarnish desirable.

Pick your answer from:
[a]. Cleaning collectible quarters can decrease their value greatly. Because of this, it is best to leave old, valuable quarters alone..
[b]. If you are planning on selling the quarter in full, take extra care to assess whether it is worth selling. The american coin association has provided training regarding handling, chiseling, and sealing quarters..
[c]. For this reason, it is important that you understand their value before introducing that quarter into your collection. Clean quarters half-way through the cleaning process..
[d]. You may want to add brushes of varying sizes to make sure your quarter is not subjected to unwanted or offensive usage. It's more to conserve the coin before storing or trading it..
[a].