Last-minute tax filers trying to beat Uncle Sam's deadline were handed free aspirin in post office lines, while others scrambled for 11th-hour tax shelters. A postal worker was injured by a letter bomb addressed to "tax thieves."

Millions of procrastinators produced the usual midnight crowds and traffic jams in cities large and small as Tax Day 1990 drew to a close.An envelope containing a tea bag in apparent reference to the tax protest that helped spark the American Revolution blew up Monday night outside the Royal Oak Post Office in suburban Detroit as workers collected tax returns. The bomb spewed a red liquid.

A 29-year-old postal worker, Tom Berlucci, was treated at a hospital for burns on his hands and face, said police and his brother, George Berlucci.

The Internal Revenue Service did not estimate how many taxpayers waited until the last minute. But the agency predicted about 34 million returns - more than 30 percent of the 111 million expected this year - would be filed after April 16.

The deadline is usually April 15, but because the 15th was a Sunday this year, the IRS delayed the deadline a day.

The IRS Form 4868 was one of the most-sought pieces of paper in the nation as an estimated 6 million Americans abandoned hopes of meeting the midnight deadline. Filing a Form 4868, along with a check for estimated taxes owed, extends the deadline to Aug. 15.

Here are some things that happened around the country:

-A woman dressed as an aspirin bottle handed out samples at the post office in Chicago.

-A Philadelphia radio station blasting rock music from a van gave away stamps.

-At Twentieth Century Investors Inc. in Kansas City, customers opened more than 130 Individual Retirement Accounts, or IRAs, in three hours.

-Michigan Treasurer Robert Bowman was among the late and bleary eyed. "I always wait until the last minute to do my own taxes because I spend the first three months of the year worrying about everyone else's. But I always get a refund," he said.

-Elliott Swinton, 27, who was among those in line at a copy machine in Philadelphia, said he did his taxes weeks ago but delayed filing them until the last minute. "We owed money. Why give it to them two months ago?" he said.

-A New York City sales representative, 24-year-old Michael Alleyne, balanced his state form on his knees on the steps of the main post office in Manhattan.

-Demonstrators, mostly those who oppose the use of tax dollars for defense or nuclear projects or who oppose paying taxes altogether, mingled in post office crowds in Philadelphia, suburban Atlanta and Greenfield, Mass.