Income tax procrastinators, file this somewhere important, maybe on the tippy-top of the pile in the shoebox: St. Paul's main Downtown Post Office won't be open until midnight on Tax Day this year, which falls on Monday, April 18.

As the clock ticks down to the filing deadline, the long-cherished tradition of panicked last-minute filers clogging Kellogg Boulevard will instead be happening at the Airport Post Office, at 5001 Northwest Drive. That postal facility will be collecting mail until, Cinderella-like, dire consequences follow the gonging of the 12 o'clock hour and the cherished April 18 postmark slips from one's grasp.

Between last Tax Day and this, the mail sorting and distribution operations at the St. Paul Post Office were moved to Eagan, said Pete Nowacki, spokesman for the U.S. Postal Service.

There are still retail postal operations at the downtown site, just not the processing. For the more casual procrastinator, the St. Paul Post Office will be open until 5:30 p.m., and the last collection from the boxes outside will be at 7 p.m.

In addition, the window at the Minneapolis Main Post Office, 100 S. 1st St., will remain open until 8 p.m. on Tax Day, Nowacki said. Mail collections will be made in front of the post office until midnight.

Late filers daring the deadline can follow the jet contrails to the Minneapolis-St. Paul International Airport or take the Post Road exit off Hwy. 5 and follow the signs.

The Internal Revenue Service expects 30 percent of the 142 million or so Americans who file tax returns -- including nearly 2.5 million Minnesotans -- to do so by mail. The IRS says 25 percent wait until the last week to file.

The Postal Service offers these tax mailing tips:

•Apply proper postage and stamps, especially with extra forms/schedules. It costs 44 cents for the first ounce. Before April 17, add 17 cents for each additional ounce. On April 17, the price for additional ounces rises to 20 cents. One ounce is about four pages, but since paper weights vary, it's always best to check or play it safe and add a stamp.

•If you use a larger envelope, first-class postage is 88 cents for the first ounce.

•Double-check the last collection time before depositing a tax return in a blue collection box on April 18 to ensure that your return is postmarked before the deadline.

•If you use a non-IRS labeled envelope, make sure you print the proper IRS address.

•Print your return address in the upper left-hand corner of your tax mail envelope.

•For tax questions, contact the IRS at 1-800-829-1040; or

Jim Anderson • 651-735-0999