CHICAGO — Memorial Day revelers left the city's beaches a garbage-strewn mess — but they were squeaky clean by Tuesday morning.

The Chicago Park District uses machines called a beach groomer and beach sanitizer to pick up the trash, said Mike Brown, the assistant director of landscaping for the Park District. The machines dig 6 or 7 inches into the sand, pulling up all kinds of trash. The sanitizer is so precise it can pull up small stones and rocks.

Kelly Bauer reports on the disappointing beach behavior of Chicagoans.

The groomer and sanitizer can usually go across an entire beach before it's full, Brown said. But there was so much trash at North Avenue Beach on Tuesday morning, one machine passed in a single line down the beach three times and was full.

“I’ve never seen it look like that, ever,” Brown said.

Fox Chicago visited the beach at dawn Tuesday:

You could barely take a step without walking on a plastic water bottle, Brown said, and the department had to bring in employees to clean the sidewalks, pathways and other areas that the groomer and sanitizer can't reach.

And it wasn't just North Avenue: Beaches across the city were covered with garbage after the three-day weekend.

“Instead of cutting grass, weed whacking, we had to put all of [the employees] on cleaning up litter this morning,” Brown said on Tuesday.

Brown said he doesn't yet know how much trash was collected from the beaches, but there might have been more litter than usual because it was one of the first warm-weather weekends of the year and a long weekend.

Another factor in the mess: Brown said he saw empty trash cans amidst the littered beaches. Other holiday weekends might get messy, he said, but they shouldn't be as bad as this one was as long as people use the trash cans.

It costs more than $4 million to clean up the litter every year, according to the Park District. That money could be used to plant 6,000 trees, rebuild 30 playgrounds or rehab 130 tennis or basketball courts, the Park District said.

The Park District has encouraged people to throw their trash out in garbage cans or, if a can is full, hold on to litter until they find another can.

The beaches will be cleaned at least once a day until Labor Day.

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