St. Paul police will hold a drive-through clinic Saturday to help vehicle owners protect their license plates and catalytic converters, two items that have been hotly targeted by thieves in recent months.

Officers will spray paint the outside of drivers' catalytic converters and install theft-prevention screws on license plates between 8:30 a.m. and 12:30 p.m. in the north parking lot of Allianz Field, the home of the Minnesota United soccer team off Snelling Avenue and I-94.

"We're going to try to make the devices a little less appealing to would-be thieves," the department said in a Facebook posting announcing the event.

Motorists are asked to register for the free event to allow police to gauge demand and have enough supplies on hand.

Nearly six catalytic converters have been swiped each day in the city, according to St. Paul police, amounting to 560 for the year as of Monday.

Criminals cut off the pollution-control devices, which are coated with precious metals like palladium, rhodium and platinum, and sell them to scrap yards — which pay up to a few hundred dollars apiece — or on websites like Facebook Marketplace that feature used car parts.

"Many scrap yards won't purchase marked catalytic converters," the Police Department said.

License plates have also been a hot commodity. During the event, police will install screws that make it harder to rip off plates, which have been taken by people driving stolen vehicles, police said.

If it rains Saturday morning, the event will be postponed.

Tim Harlow • 612-673-7768