The District has a pretty good game going. Sort of like being the house in Vegas.

Here's how it works: The city requires the removal of old registration stickers from the windshield -- but the glue is ultra-sticky so residents have trouble getting it off. D.C. police, meanwhile, are giving out tickets for displaying expired permits. It doesn't matter if the new permit is in place; displaying the old one is an offense.

Dr. Gridlock invited readers to offer ideas for removing the stickers. This is a District problem, but these solutions may be useful to others:

Dear Dr. Gridlock:

The last time I replaced my sticker, I had fairly good success using a hair dryer to remove the old one. After blasting it for a few minutes on high, the glue became more brittle, and the sticker pulled off fairly cleanly with a little help from a razor blade.

Jason Waanders

Washington

I have found the best way is to remove the bulk with a single-edged razor, and the remaining glue with WD-40.

Allow the WD-40 to set for a minute, then wipe with a wet cloth.

Mike Mallach

Washington

I have had good luck with Windex to soften the sticker and glue and a single-edged razor to scrape the sticker from the windshield. It takes 10 to 15 minutes.

I bring plenty of paper towels to the car to keep the Windex from dripping on the dashboard.

Suzanne Hazard

Washington

A cleaning product called Goo Gone will work. Spray or squirt it on, and the sticker can be easily scraped with the windshield ice scraper.

The only other thing that even partly worked before was nail polish with acetone -- and that still required a putty knife.

Kristine Roth

Washington

The Department of Transportation spokesman you cited obviously has never tried to remove a windshield sticker (use a single-edged razor blade). I went to Strosnider's Hardware, where they recommended a scraper with a reversible blade made by Allway Tools (model number GTS 07400).

It wasn't easy, but it did the job -- and a little Goo Gone helps with the leftover adhesive.

Naomi Glass

Washington

You would think police have better things to do, like address the No. 1 cause of gridlock: illegally parked vehicles taking up lanes during rush hours. But, no, these $15 expired sticker tickets are important.

Here's what D.C. Department of Motor Vehicles spokeswoman Janis D. Hazel recommends: "Motorists can use a window scraper called a sticker/gasket scraper, which comes with a single-edge razor blade and can be found at auto supply stores.

"Also, employees at the inspection station at 1001 Half St. SW will remove stickers from customers' vehicles as a courtesy if the lines of waiting customers are not too long."

Which Line Is Most Crowded?

Here's a Metro problem: Rank the five lines (Red, Orange, Blue, Green, Yellow) in order from the most crowded to the least. The answer will be in this Thursday's Extras and repeated next Sunday, maybe with the winners (depending on how many there are). One entry per person, please. The deadline is Wednesday.

Take Metro, Keep Your Car Safe

Dear Dr. Gridlock:

The best reason to take Metro when visiting or doing business in the District of Columbia is to keep your car from being stolen.

Maybe Metro management could get an endorsement on this from Chief Charles H. Ramsey.

K.J. Dolney

Alexandria

Ouch! Well, city officials would be happy if more people came into the city via mass transit; of course, this tongue-in-cheek suggestion is well over the top. Wouldn't it be nice, though, to have no vehicles in the city? Trolley cars running everywhere. Horse and carriage rides. Sleigh rides. Village squares. It once was that way. Until we discovered progress.

Transportation researcher Diane Mattingly contributed to this column.

You can write to Dr. Gridlock at 1150 15th St. NW, Washington, D.C. 20071. He prefers e-mails at drgridlock@washpost.com or faxes at 703-352-3908. Include your full name, town, county and day and evening telephone numbers. Dr. Gridlock cannot take phone calls.