It is arguably one of Downtown's most handsome streets. But Mayor Luke Ravenstahl's stroll down Penn Avenue near the convention center yesterday wasn't about the brick sidewalks, stately facades and leafy canopy.

It was a time for picking nits, with an eye toward sprucing up for the G-20 world economic summit in September.

"We have some minor work to do, but my quick assessment is that things look pretty good right now," Mr. Ravenstahl said during a pause in his walking tour at Ninth Street and Penn. "This is a great street."

To be sure, there were several visual pockmarks amid the grandeur.

"It's a bird. It's a plane," read some of the graffiti on the side wall at 933 Penn. The city will ask the property owner to sign a release form allowing public works crews to erase it.

Public Works Director Guy Costa said the city will work with the Pennsylvania Department of Transportation to remove the temporary orange road work signs, anchored with sandbags, that clutter the sidewalks.

Metal tree grates will be filled with pea gravel to discourage or mask the deposits of cigarette butts. The Pittsburgh Downtown Partnership also has ordered 20 more urns that attach to garbage cans for disposal of butts, said Mike Edwards, president and CEO.

Thirty-four empty storefronts in the vicinity of the David L. Lawrence Convention Center, on Penn, Liberty and Fifth avenues and Sixth and Wood streets, will be fitted with artistic window treatments. They will stay in place after the summit, set for Sept. 24 and 25, Mr. Edwards said.

About 30 dead or dying trees will be replaced, Mr. Costa said.

Crews also will paint street poles and hydrants, repair and power-wash sidewalks and fix street signs, starting Monday night, Mr. Ravenstahl said -- part of the $10 million to $20 million the city expects to invest in the two-day event (including public safety costs).

The Downtown Partnership will hire three or four extra members for its "clean team," Mr. Edwards said. He is concerned about a possible surge in graffiti during the summit.

The mayor's tour took a decided turn for the worse at Exchange Way, an alley parallel to Penn Avenue that slices from Ninth to 10th Street.

Stepping gingerly around potholes filled with rainwater, Mr. Ravenstahl saw Dumpsters scattered hither and yon, litter, run-down facades and plenty of graffiti.

Sure, it's an alley, but it occupies the front-door view from the Westin Convention Center hotel. "We'll be giving it the same attention [as other streets]," the mayor said. "This will be a corridor. People will be walking here."

The street will be repaved, as will several others in the district. The city will clean up graffiti and paint facades on the alley, with the permission of building owners (who won't be charged). Dumpsters will be moved or taken out altogether, and lighting will be upgraded.

Kevin McMahon, president and CEO of the Pittsburgh Cultural Trust, said the convention center district will see a reprise of the Pittsburgh 250 Festival of Lights, which decorated the city for its birthday party last October. Lights will be strung in trees and projected onto building facades and possibly the convention center, starting on the weekend before the summit.

He joined the walking tour and presented city officials with a binder of to-do items, including photos of eyesores that need attention.

Mr. Edwards said business interests and public officials have begun to coalesce after an initial period of "complete chaos" that followed the White House announcement in May that Pittsburgh would host the summit.

"We're very appreciative that the mayor's taken an interest in what's going on," he said as the tour concluded.

"It's extremely important to us," Mr. Ravenstahl said of the summit. "We can't wait to show the world all the wonderful amenities Pittsburgh has to offer."