All the oil leaked from an off-shore storage tanker and washed up on the beach at Blackpool has been removed, the council said.
But Environment Agency advice to stay out of the sea will remain in place until experts watching the tides are confident no more oil is washing ashore.
The clean up operation is continuing in Wyre, and now focusing heavily on Knott End and Pilling sands. Most of the beach at Cleveleys and Fleetwood is clear.
Some 11 tonnes of oil, sand, and stone have been removed by experts this week, ahead of the school summer holiday, which starts today for most.
The clean up operation began on Sunday, when oil washed up at Bispham in what was initially described as a 'small' problem by the Coastguard service.
It escalated the following day when oil began washing up as far south as the mirror ball in Blackpool, and as far north as the River Wyre.
Samples sent to a lab in Edinburgh later showed Eni UK's offshore storage installation, in Liverpool Bay, as the source.
The oil giant said between two and 20 tonnes of oil leaked there last Monday, and said it informed authorities 'immediately'.
Since then, it has been heavily involved with the clear up, and made the subject of an investigation by the Department for Business, Energy and Industrial Strategy (BEIS).
A specialist group has been set up to monitor any impact on marine and wildlife, though there have been no reports of any as yet. One expert said the effect could be devastating.
Dog walkers have been warned to keep their pets away from an oil, or to avoid the beach altogether. Anglers can fish as usual, though their haul may be 'tainted', albeit safe.
Anybody who has come into contact with the thick tar-like substance should not suffer any lasting effects, but should seek medical advice should they start to feel unwell.
The Fleetwood to Knott End ferry service remains suspended.
The shellfish beds at Knott Spit and Sea Centre South in Knott End are also closed.