(CBS) -- City Hall is testing a new way to rid Chicago of rats: dry ice.
You heard that right.
Dry ice is carbon dioxide in solid form, and as it melts it transforms into a suffocating gas.
Rodent removal crews drop chunks of it into rat burrows and then seal the holes. Experts say this method is more humane and cheaper than poison.
Chicago's Streets and Sanitation Department tells CBS 2 it has been successfully testing this new method in four parks and in planter boxes.
Next Tuesday, the department is planning a show and tell for the news media.
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