DEPTFORD TOWNSHIP, N.J. — Marcelle Shriver has about 80,000 cans of Silly String. All she needs is a way to get them to Iraq.

For almost a year, the New Jersey woman has been collecting Silly String to send to troops, who use it to detect trip wires connected to bombs. She's already shipped about 40,000 cans to Iraq through the military but is struggling to find someone to send another shipment.

"They're sending these cargo planes over there every day, and I know that my shipment would be a speck on one of those planes," said Shriver, standing near boxes of string stacked outside at a friend's business.

Lt. Col. Christopher Garver, a military spokesman in Iraq, said Shriver's efforts are appreciated, but commanders decide which items troops need. He said the spray was used heavily in 2004 but is not as widely needed today.

"If commanders on the ground are screaming that we need this stuff, we'll get it to them," Garver said.

Shriver's Silly String campaign began last fall with a collection box at her church. Word quickly spread, and people across the country began sending her Silly String or products made by other manufacturers that go by names such as "party string" or "crazy string."

Shriver got the idea from her son, a soldier in Ramadi. Before entering a building, troops squirt the gooey substance, which can travel about 10 to 12 feet, across an area. If it falls to the ground, that's an indication there are no trip wires. If it hangs in the air, troops know they may have a problem.

She sent about 40,000 cans in January through the Naval Air Station Joint Reserve Base Willow Grove in Pennsylvania. Other cans went to Fort Dix for troops training to go to Iraq.

Since then, Shriver has run into roadblocks as she tried to find someone in the military who'd authorize the shipments.

Normally, care packages to troops can be shipped through the U.S. Postal Service. But since the string is an aerosol, it's considered a hazardous material and has stricter shipping controls.

A Willow Grove spokeswoman, Sherri Jones, said the base had space available on a cargo plane going to the Middle East, so it took Shriver's first shipment. But, Jones said, the base rarely knows in advance when it will have a plane headed to Iraq and doesn't have space to store cans of Silly String.

Capt. Anthony Duggan, a spokesman for McGuire Air Force Base, said the Department of Defense prohibits the transportation of items that don't meet certain guidelines. For example, items sent must be in direct support of the military mission, he said.

Shriver, who isn't taking donations right now, isn't sure what she'll do with all the cans she's received if she can't get them to Iraq.

Her daughter, Jenni Smith, 35, said while her mother has been constantly worried about delivering the string, the campaign has had a silver lining.

"I think it has kept her mind off the fact that my brother is where he is," Smith said.