Rudy Asercion, executive director of the West Bay Pilipino Multi-Service center in San Francisco, right, hugs Arturo Marasigan, as he prepares boxes of donated items for victims of Typhoon Haiyan in the Philippines.

Faced with heartbreaking images of the typhoon-ravaged Philippines, the world is watching an epic tragedy unfold and looking for ways to help. The big question is how.

In the aftermath of mega-disasters such as Typhoon Haiyan, experts say there are some basic rules for those eager to do good: Forget the rummage sale clothes, the old toys and the kind of supplies that will only stack up undistributed or damage an already weakened economy. Do send a cash donation to a respected charity.

“It absolutely should be money,” says Kathleen Tierney, director of the Natural Hazards Center at the University of Colorado-Boulder, a clearinghouse and research group on the social aspects of disasters around the world. “Whether it’s the U.S. or abroad, one thing that typically happens after a major disaster is people want to donate stuff. This creates enormous logistical problems ... and people receiving donations they could never conceivably use, like winter coats sent to people in the Caribbean.”

When disaster aid isn’t properly thought out, “you can end up undermining the local economy,” Tierney adds. “Once you ship building materials halfway around the world, it turns out you’ve ruined the market” for those in the area. “If you want to see economic recovery, you don’t want to send so many supplies that you create a situation where people can’t survive in a business sense.”

The Red Cross, for instance, buys goods locally or domestically after disasters to help revive the economy, curb transportation costs and help guarantee culturally appropriate items are being used, says Jana Sweeny, the organization’s director of international communications.

Sweeny says there’s a natural tendency for people to want to help after headline-making catastrophes, but that altruism can sometimes be misguided.

She recalls in the days after Hurricane Katrina when storm survivors were evacuated to the Houston Astrodome, someone sent thousands of pounds of cheese — a shipment far too big for any refrigerator there to hold. Another well-meaning donor dispatched a truckload filled with patent leather shoes.

“People absolutely have good intentions,” Sweeny says. “Many of us see people who’ve lost everything. They’re standing there with nothing. The instinct is that anything will help make their lives better. But that’s not always the case.”