ANCHORAGE -- Exxon officials have declared this summer's assault on the nation's worst oil-tanker spill a success and promised to return next spring to look at oiled beaches, if not to continue cleaning them.

"Everything that could have been done in a sound environmental manner has been done," Otto Harrison, the company's cleanup chief, said at the summer's last public meeting Tuesday night of the multiagency Exxon Valdez oil-spill cleanup steering committee.

By Friday night, the last cleanup crews in Prince William Sound will be pulled into port in Valdez or Seward to end this year's effort, he said.

Exxon's summer work force was about one-tenth of the number mobilized in the summer of 1989 to mop up oil spilled March 24, 1989, when the grounded Exxon Valdez tanker spewed about 11 million gallons of crude oil into the sound.

If Exxon refuses to do more work on soiled beaches, the state may hire a contractor for the work and bill Exxon, said Randy Bayliss of the Alaska Department of Environmental Conservation.

Meanwhile in San Diego, two members of the environmental-protection group Greenpeace handcuffed themselves to the rudder shaft of the tanker, now named Exxon Mediterranean, as it tried to leave port for the Mediterranean Sea. The 987-foot vessel moved out of its berth after missing the early tide. Fog then delayed its departure from the harbor.