Playing Hurricane Katrina remains the key investing issue right now, James Cramer said on his "RealMoney" radio show Tuesday.

The short-term trade was probably last week, said Cramer. Be careful with Shaw Group ( SGR) and Caterpillar ( CAT), he said. Even though Shaw will benefit short term from New Orleans reconstruction, the stock has already had a big move, and long term, its core business of environmental remediation is threatened by national energy priorities. Caterpillar has also had a big move, but Cramer likes the stock on a pullback. Also, be wary of cement stocks. That trade "seems over to me," said Cramer.

Nevertheless, to make money in the short term, think about what the Federal Emergency Management Agency and the Department of Homeland Security need right now. The most obvious need, said Cramer, is for emergency equipment, which is basically camping equipment: tents, cooking, water purification, flashlights, sleeping bags, etc. The brand that dominates the camping equipment market is Coleman, said Cramer. Coleman is owned by Jarden ( JAH). "That's a trade," said Cramer, who thinks Jarden has a "couple more points to go."

Also, Lowe's ( LOW) and Home Depot ( HD) are going to make money, said Cramer. Cramer, who had been bearish on Lowe's and Home Depot before the hurricane, said, "I was wrong. I did not anticipate a catastrophe on this scale. ... This wasn't a hurricane. It was gotterdammerung."

Cramer also likes Phelps Dodge ( PD) in the short term. Even though he had advised selling Phelps Dodge a few weeks ago, "Hurricane Katrina changed some things," Cramer said. New homes have 400 pounds of copper, said Cramer, and PD should benefit.

Long term, Cramer was bullish on oil, communications and insurance. We're not finding more oil, said Cramer. We don't have enough, and we'll never have enough going forward. The long-term picture is one of scarcity.

Refineries are currently the bottleneck, and the refinery play Cramer recommends is Valero Energy ( VLO). Valero, "should be a core holding," said Cramer. Use the recent weakness to buy some shares, he said.

Companies that own energy resources should also do well. Cramer recommends EnCana ( ECA), Marathon Oil ( MRO) and Chesapeake Energy ( CHK). "Pick them up here for the long term," Cramer said.

As for communications, Cramer said cell-phone towers will have to be added and we'll have to put more antennas on the towers we have. Cramer recommends American Tower ( AMT) and Global Signal ( GSL).

Insurance carries should be able to raise rates in the wake of the hurricane. Cramer likes Montpelier Re ( MRH), Argonaut Group ( AGII) and American International Group ( AIG).

Cramer focused on the homebuilding sector in Tuesday's Sector Spotlight. In response to an email question about Comstock Homebuilding ( CHCI), Cramer said, "I don't see a lot here." Cramer said the bear case for homebuilders included a dramatic rise in raw costs for wood and building supplies. Additionally, recent news articles have suggested the Washington, D.C., housing market, Comstock's home market, had cooled. Cramer said Comstock was "down too much to sell." But, he cautioned, just because a stock is finished going down doesn't mean it is going to start going back up again.

Another emailer asked about Centex ( CTX). Cramer said Centex was the cheapest homebuilder and has a "huge presence" in Texas. Centex should benefit from rebuilding along the Gulf coast.

Toll Brothers ( TOL) is too expensive, said Cramer.

Beazer Homes ( BZH) is "good," but it is "too high relative to its 52-week high."

D.R. Horton ( DHI) is too expensive relative to other homebuilders and is barely down from its 52-week high. "I don't want to own it," said Cramer.

A caller asked regarding Cramer's stance of focusing on high-end retail plays whether Costco would be considered low end or high end. Cramer said he feels Costco is not high-end, but it should be.

A caller asked if Todco ( THE) had suffered much damage in Hurricane Katrina. Cramer said Todco is presenting Wednesday at a Lehman Brothers energy and power conference. Cramer recommended not making a move in Todco's stock until you hear what the company has to say.

In response to a question about 7-Eleven ( SE), Cramer said he would "ring the register."

Cramer also commented on Clorox ( CLX) as a possible Hurricane cleanup play. Cramer said he liked Clorox but not for the hurricane cleanup. Although Clorox may spike short term, Cramer likes Clorox long term as a play on a slowing economy.

Finally, in response to a question on Halliburton ( HAL), Cramer said oil service stocks like Halliburton were not doing well. But, unlike other oil service stocks, Halliburton has a construction business, which should benefit from the hurricane rebuilding effort. However, Cramer recently sold some of his Halliburton holdings because the stock has had a big run.

At the time of publication, Cramer was long EnCana and Halliburton.

James J. Cramer is a director and co-founder of TheStreet.com. He contributes daily market commentary for TheStreet.com's sites and serves as an adviser to the company's CEO. Outside contributing columnists for TheStreet.com and RealMoney.com, including Cramer, may, from time to time, write about stocks in which they have a position. In such cases, appropriate disclosure is made. To see his personal portfolio and find out what trades Cramer will make before he makes them, sign up for Action Alerts PLUS. While he cannot provide personalized investment advice or recommendations, he invites you to send comments on his column by clicking here. Listen to Cramer's RealMoney Radio show on your computer; just click here. Watch Cramer on "Mad Money" at 6 p.m. ET weeknights on CNBC. Click here to order Cramer's latest book, "Real Money: Sane Investing in an Insane World," click here to get his second book, "You Got Screwed!" and click here to order Cramer's autobiography, "Confessions of a Street Addict."

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