In "These Stocks Will Burn You," I cautioned against getting too excited about the potential for making millions in small-cap stocks. Not because small companies lack the chance for big gains; I could give you any number of examples that have scored big, such as eBay (NASDAQ:EBAY) and SanDisk (NASDAQ:SNDK). Up 152% and 212%, respectively, over the past 10 years, a $10,000 investment in each of those would have you sitting on more than $50,000 right now.

No, my warning was simply to let you know that with such high potential reward comes high risk. It's one of the laws of investing, one we teach about constantly in our Motley Fool Hidden Gems small-cap investing service. You need to do all you can to avoid having a stock or two inflict years' worth of damage on your portfolio.

So how can we Fools reduce the risk involved while still keeping the potential reward high enough? First, we can pay attention to the balance sheet, and stay away from companies that are overleveraged with debt and burning through lots of cash. In my original article, I recommended sticking with profitable companies with cash-to-debt ratios of at least 1.5. That became particularly important with the recent financial meltdown, which devastated overly leveraged businesses.

Second, we can buy two, three, or even more of these small fries with the same amount of cash we'd normally allocate to one position. If $6,000 is all you're comfortable allocating to a "normal" stock purchase, try buying three small caps you like at $2,000 apiece. That way, if one crashes to earth and loses half its value, your portfolio won't be too harmed by it.

For example
A good example comes from the small caps I've bought from the recommendations in Hidden Gems. I bought Buffalo Wild Wings, Cutter & Buck, and Cutter & Buck, a Tiny Gems micro-cap recommendation, was down 25% for me before it was bought out by a Swedish firm. However, I'm also sitting on current gains of 37% in Buffalo Wild Wings and 90% in Ctrip. If we assume (for simplicity's sake) a $2,000 investment in each, my $6,000 would have turned into $8,035: a nice 34% gain, despite Cutter & Buck's quarter "haircut."

Of course, larger companies can be volatile and burn you as well: Consider that Yahoo! (NASDAQ:YHOO) and Hewlett-Packard (NYSE:HPQ) lost 60% or more in the great Tech Wreck of 2000. And we scarcely need to mention companies that have been taken down by the financial crisis, including "blue chips" like Freddie Mac (NYSE:FRE), AIG, Washington Mutual, and Citigroup (NYSE:C). But you must be especially on your guard with small caps.

How to get small
Despite the risks, the promise is there -- and we actively encourage you to make small caps a part of your portfolio, especially if you have a few years to go before retirement. If you need help separating the wheat from the chaff, and you want to find out which five small companies our analysts suggest you buy now, consider a trial run with Hidden Gems. Here's more information on a no-risk free trial.

This article was originally published on Dec. 5, 2006. It has been updated.

Rex Moore is a Fool analyst and looks great in flannel. He owns shares of Buffalo Wild Wings,, and eBay. Buffalo Wild Wings and Ctrip are Hidden Gems selections. eBay is a Stock Advisor selection. The Fool owns shares of Buffalo Wild Wings. This information is brought to you by the Fool's disclosure policy.