Click here for an archive of Jim's Mad Money Recaps. Jim Cramer ate a plate of crow at the beginning of his "Mad Money" show Wednesday night. It pained him, but he told viewers on CNBC that he got it wrong on Symbol Technologies ( SBL). "This is a company that almost killed me," Cramer said. Cramer said he had bought the stock some time back because he thought it would be a great homeland-security play. He figured the U.S. government would be buying radio frequency identification technology from Symbol, and then the money would come tumbling in. So he bought. And then he waited. And waited some more. The stock just kept going down. Eventually, Cramer sold the stock at right around $10. So what caused Cramer's humility Wednesday night? The secretary of Homeland Security, Michael Chertoff, announced a massive restructuring today. He is going to spend a lot of money on technology. And, Cramer, said, that means Symbol is poised to win contracts. So why didn't the stock move on the news? Because, Cramer said, too many people lost money the first time around. There are still too many disbelievers. So where to for Symbol from here? Cramer said that he blew it, but other investors don't have the baggage he does. As such, "You can go out and buy it now," he said. Moving on to the callers, someone wanted to know what he should do when a stock he owns has gone down. When do I sell and when do I buy? the caller wondered. Cramer said that if the stock was bought as a trade, you blow out of it. If, however, the stock was bought as an investment, then you do more homework and decide if you want to buy more. Remember, Cramer said, "It's called buy and homework."