It's no secret that in this economy many people need to liquidate assets, including rare coins.

We're in a buyers' market, cash is scarce and demand has fallen considerably since just six months ago, except for many common date gold coins. The five-year-long bull market ended last year and many prices have suffered since.

High quality for specific grades is appreciated and rewards sellers with higher paybacks than for coins of average quality for their grades. Off-quality coins for specific grades really get slammed. The low-end coins are those that just make the grade or have problems that are not significant enough to be mentioned on the grading holders.

Some factors that cause coins to be off-quality are weak strikes, spots, hazy or ugly toning, light cleanings, hairline scratches and large rim nicks. They are in contrast to qualities that add value to coins, like outstanding luster, cameo devices, strong strikes and great toning. Such coins routinely sell for premiums over average quality coins.

The problem for collectors who have unwittingly been sold coins that just make the grade reveals itself upon reselling the coins. Buyers, when they can be found these days, either won't buy these coins at all or will only purchase them at deep discounts.

So what should collectors do?

First, rest assured that probably most coins graded by the top tier grading services are acceptable to the marketplace. However, not all coins graded by all grading services trade for similar values.

It's a fact that, overall, collectors in the market predominantly want coins graded by either Numismatic Guaranty Corp. or Professional Coin Grading Service.

This should not imply that coins graded by some other services aren't wanted or are inferior. But simply put, coins graded by NGC and PCGS routinely bring more money than coins graded by other services.

Second, collectors should sharpen their grading skills.

Third, if you believe you have coins that are at the low end of the grading scale, consider trading them to dealers for other coins. Trading is an emerging trend in today's market.