WHILE MANY good people in and around Greater Washington do volunteer regular time to help feed their less fortunate neighbors day by day, not everyone can devote time to the operations carried on by some 270 agencies -- soup kitchens, church pantries and the like -- in the area. But many have found an easy and effective way to do their part, through a cooperative volunteer "food bank" that has been doubling its "revenues" -- contributions of canned food -- with each special campaign it conducts. Now nearly five years old, the Capital Area Community Food Bank distributes 300,000 pounds of food each month.

This week, the annual fall collection is in progress at area Giant Food and Safeway supermarkets, where customers are being invited to toss cans of food into specially marked shopping carts beyond the checkout counters. In addition to the assistance of the two food chains, help in the drive is being provided by the D.C. National Guard, which is transporting the food from more than 200 stores to the food bank; and Local 400 of the United Food and Commercial Workers Union, whose members are stationed at the carts.

Nobody knows how many more years the annual campaign can hope to double its collection, but obviously this year's effort is seeking to attract new depositors -- and their operation is simple and direct. Whatever comes in will go out, helping to feed more than 100,000 residents who rely on local agencies for meals. That's a solid yield from a modest investment.