Mary Heins walked into her garage last June to get a rake when she discovered something more urgent than the yard work.

The brick wall where the rake was hanging was dented in.

"It was really dangerous looking," said Heins, 61. "If somebody pressed too hard, they could get bricks falling down on them."

Heins, a retired postal worker, investigated the damage and concluded that one of Denver's garbage trucks must have shoved a dumpster into her garage.

"The dumpster was right in front of it, and the dent was in the same place, at the same level," said Heins, who is on a long list of homeowners who blame the city's garbage and recycling trucks for trashing their property.

Although drivers are continuing to knock down fences, bang up walls and cause other mayhem, especially in older neighborhoods with narrow alleys, they're starting to clean up their act.

In February 2007, the Rocky Mountain News reported about the thousands of dollars in property damage claims involving the city's trash and recycling trucks.

Since then, the number of claims has dropped 30 percent, from 173 to 121.

"There's still horror stories out there, and we know that," said Lars Williams, operations manager for the city's Solid Waste Management division.

"But I think probably the biggest thing is we've tried to be more sensitive to people's problems when we do damage property," he said. "We've (also) tried to very much increase our training and awareness with our drivers and (teach them) how to avoid property damage."

Part of the problem is the age of the city's 17,000 dumpsters. If the hooks used to lift them are rusted, they snap off easily, said driver Mark Duran Sr. "You won't know what's going on until you're coming down with that box," he said. "They just fall right off the truck."

The city tries to replace as many dumpsters as possible every year, but the budget crunch is slowing the effort, Duran said.

When drivers notice rusted or damaged hooks, they call a city repair truck to replace the hooks or the dumpster. Drivers also are instructed to do regular maintenance on their trucks' lifting mechanisms and look for problems on their routes, such as a dumpster being too close to a garage.

Still, Williams said, accidents are going to happen.

Consider the numbers, he said. Drivers log about a million miles annually. The city collects trash from about 165,000 households every week and recyclables every other week from 80,000 households. There are usually 80 but up to 100 trucks at work. Garbage trucks are 30 feet long. The right of way in some alleys is 8 feet.

"Our exposure rate is huge," Williams said.

Mike Vigil, the department's operations supervisor, said he had accidents when he was driving.

"I knocked down a telephone pole," he said. "Instead of dumping the dumpster and setting it back down, I just got in and drove off. Boom! I ran right into that telephone pole."

Heins, who is trying to collect money from the city for the damage to her garage, said she has sympathy for the drivers.

"They have overhead electrical wires to contend with and then they have cables coming down off of poles, and then the narrowness of the alley itself," she said. "It'd be like threading a needle."

Still, Heins wants the city to pay up. The city attorney's office is reviewing her claim, a public works spokeswoman said Friday.