They started arriving at Poldhu Cove on Sunday, and National Trust volunteers have been clearing them away as they think it could be dangerous for wildlife.
The bottles are sealed closed, but it's thought that some may have leaked.
The National Trust said it thinks a container had gone overboard from a ship during stormy weather.
Other nearby coves including Gunwalloe, Polurrian and Marazion have also been affected, conservationists said.
Members of the public have been told to keep small children and dogs a safe distance away, whilst the clean up continues.
Justin Whitehouse, from the National Trust, said: "The main worry is all that detergent going into our beautiful marine environment, but thankfully most are full."
Thousands of bright pink plastic detergent bottles have washed up on beaches in Cornwall.