Don't automatically shred those credit card offers arriving in your mailbox. They just might contain an attractive rewards program.

Card issuers grew stingy with rewards during the credit crunch and while they waited to see how much federal card reforms would hurt their bottom line, card experts say. But now that those matters are behind them, banks have been reviving rewards to make their cards stand out.

"They are back, and they are back with a vengeance," says Curtis Arnold, founder of CardRatings.com, a credit card comparison site.

Two-thirds of credit card offers in September featured a reward or rebate, according to Synovate, which tracks direct-mail solicitations. Though that's less than in June, rewards since that time have become more generous, says Synovate's Roy Persson.

Cards offer enough airline miles now that you can qualify for a round-trip ticket fairly quickly, or you can earn $100 to $200 cash back for meeting modest spending hurdles.

And issuers are expected to sweeten deals for the holidays to reel in consumers just when they are likely to do some serious charging. Discover, for instance, is promoting a cash-back card with a $150 holiday bonus to consumers who spend $1,000 in the first 90 days.

Of course, there's a catch. Rewards aren't back for everyone. Card companies are being highly selective and in pursuit of the same customer: the one with excellent credit.

These days, that's someone with a credit score of 750 or higher out of a possible 850 points.

Those with good credit — a score of 700 to 749 — also may qualify for some of these rewards cards, but at a higher interest rate.

Bill Hardekopf, chief executive of the card comparison website LowCards.com, says issuers are being so picky to limit their risk. It's one of their lessons from the recession. Before the economy tanked, card companies handed out plastic with generous limits even to those with shaky credit.

"When the downturn hit, people started defaulting," Hardekopf says. "Credit card issuers were left holding the bag."

But trying to attract the best customers isn't the only reason issuers are beefing up rewards. Card companies figure by offering such enticements, Hardekopf says, you're more likely to use a credit than a debit card.

New federal rules limit the fees banks can collect for processing debit card transactions for merchants. There is no such cap on credit cards, so banks earn more if you use that plastic. Plus, if you don't pay your balance off each month, issuers can collect interest.

Certainly, banks are making credit cards more appealing. If you're in the market for more plastic, online card comparison websites can help you narrow your search. Here are some other tips:

Get out the magnifying glass Make sure you read the fine print, and the print isn't any finer than in credit card agreements.

With Discover, for instance, you can earn up to 1 percent cash back on purchases, plus as much as 5 percent on certain categories. But you will never earn more than 0.25 percent on purchases at a warehouse retailer, says CardRatings' Arnold. If you often shop these stores, another reward card might be better.

The Chase Freedom Visa also awards 5 percent cash back on the first $1,500 of purchases made in select categories during a quarter.

But each quarter, the issuer switches the categories, says Beverly Harzog, a credit card expert for the card comparison site Credit.com. And you must enroll every three months for your purchases to get the 5 percent rebate, otherwise you will earn only 1 percent, she says.

Other cards have quarterly enrollments, too. Card issuers say they do this so customers remain engaged and become more familiar with how their card works, says CardRatings' Arnold. But he says it's just one more thing a busy consumer must remember — or forget.