Rain-soaked old sofas sitting out on curbs for days tend to anger permanent downtown residents.

But the city and the College of Charleston are working together to make sure trash is collected - including adding an extra collection - after Thursday, the end of the month when leases for a large number of students who rent downtown apartments expire. They also are encouraging renters to contact Goodwill to donate usable items instead of throwing them in the trash.

Evie Nadel, the college's senior director of community relations, said the college has contributed $2,000 toward Operation Move-Out, which is the effort to collect it.

The area of the peninsula most affected by the end of July move-out has been divided into three zones: zone one runs from Line Street to Cannon Street; zone two runs from Cannon Street to Calhoun Street; and zone three runs from Calhoun Street to Beaufain Street.

City code enforcement officers yesterday began patrolling the zones to find locations where large amounts of trash are being thrown out. They will patrol through Friday.

Then on Saturday, the city will run an additional collection to gather items placed on the curb.

Ten volunteers from Keep Charleston Beautiful will help with the effort.

Tenants also may place their trash on the curb after 6 p.m. Sunday for regular Monday pickup.

Reach Diane Knich at 843-937-5491 or on Twitter at @dianeknich.