A woman walks into Mike's S.W. Liquors, hands the owner, Mike Fingerman, a $10 bill and walks out with an empty Senate beer can.

A father who has a reputation for his intake of beer buys a case of 24 different cans, paying $17 rather than the $6 or $7 a case he normally spends, so that he can help add to his son's collection of beer cans.

A politician drops in and buys 10 or 12 cans. The cans are taken to a back room and poked in the bottom and the beer poured into a sink. The cans are then packed for easier handling for the flight to his home state.

"Saturdays, it's like a picnic around here, all these kids come in with their parents from all over the place and buy beer cans," said Fingerman.

"It's a phenomenon we have never experienced before in the liquor business," Fingerman says. "I've been in this business for 30 years and I have never seen anything like this."

The beer can collecting which has just recently made such an impact in the Washington area has actually been a hobby for a lot of people for a long time.

People have been collecting for 30 or 40 years and they have an association called the "Beer Can Collectors of America."

BCCA was founded in 1970 when six Midwestern men got together, and they now have 11,600 members who frown upon laying money out for beer cans.

Rich Allen, a member from Springfield Va., said, "The association is only interested in swapping, not buying."

To help its members keep up with what's new in beer cans, the BCCA publishes a bi-monthly news letter. To whet the beer can collectors thirst, the Falstaff Brewers have a brand called General, and have started a presidents' series.

Two are now on the market, Washington and Adams. Beneath each photograph they have a saying like Washington's, "I never told a lie."

The brewers plan on coming out with a new label every 90 days.

When is Nixon going to be on the market? That's up to the collectors to figure out. A good guess would be close to nine years.

Over at Circle Liquor on Connecticut Avenue Max Bricker, the manager, said, "Kids are bringing Daddy in and pick out the beer for him, sometimes they come in and scout around themselves.

"It's amazing, but it's the kind of hobby that gets cooperation.

"No matter what kind of kooky beer we get, sometimes it's beer we wouldn't even handle, but they buy it."

At the Sheffield Wine and Liquor Shop, also on Connecticut Avenue, owner Al Horwitz said, "Its a drag. Kids come in with their mother or father and buy one beer out of a sixpack.

"Sometimes we know the parents and they are customers but a lot of strangers come in and buy one can. We do pretty good in this neighborhood. We have a lot of collectors around here."

The kids who collect the cans are not standing outside the barrooms singing songs like, "Daddy, dear old daddy, won't you come home with me now." They want the old man to hang in there and bring out the empties.

Maurice Coja, who owns a restaurant called the Brickseller and has over 400 American and imported beers for his customers to choose from, told a story about a customer who came and plunked a $20 bill on the bar and said, "I'm here drinking beer so that I can bring the cans home to my kid. He gave me the money he saved and promised to do his home work."

And he had a list of the cans his son wanted.

The Brickseller, on 22d Street near P, is a museum of vintage and unusual beer cans, and Coja said, "There is no other place in the world with a larger variety of beer that you can buy across the bar."

The walls are lined with display cases showing labels that could bring back lots of memories for people and maybe a few headaches.

The cans are for sale and range in price form 50 cents up to several hundred dollars for a rare "Cooks 500 Ale," can.

The James Bond "007" cans sell for close to $200 apiece. The brand sold by the National Brewery in Baltimore was taken off the market after the Bond people went to court and filed an injunction against the brewery.

A beer labeled "Soul" that never got off the runway because of the Watts riots when the brewery was destroyed, is also high on the price list. The brewery, the first black-run operation in the business, printed empty cans for the salesman's use and that's about as far as they got.

Only the empty display cans used by salesmen for samples and have never held beer are considered "mint condition" for collectors.

The beer sold at the Brickseller is always opened from the bottom to keep the top perfect. "My bartenders don't know how to open them from the top," Coja said.

Coja claims exuberantly that beer can collecting has done a lot in reuniting American families. "Kids get to collecting cans and begin to talk to Dad and they get involved together. The kids learn a lot, they learn geography from the labels on the cans.

"They learn to talk to people while trading or collecting. "They learn the value of a dollar, it is an education in itself."

To help the collectors there is a catalog called "The Beer Can Collectors Bible" and another called "Beer Cans Unlimited." They are hard bound and sell for about $24.

The pages are lined with 7,000 or 8,000 color illustrations of every beer can ever produced. They are number coded to a price list along the bottom.

Tennents Brewery in Scotland has a label showing pin-ups. The series started in World War II when they brewed beer for the British Navy, and being broadminded the admiralty liked the idea and went along with it to help the British Tars' Morale.

There is a famous painting series showing Rembrandts and other painters of the Flemish school, brewed by a Swedish firm.

In Sweden, a country that has always been advanced in its social concerns, a brewery called Lys Ol produced a porno label along with a risque limerick two years ago that might make the beer drinkers crosseyed as he sipped his evening lager.