From the Star-K website:
“Strawberries
Checking Instructions
Please note the following regarding all Star-K insect checking instructions: When applicable, guidelines apply to produce grown and purchased in the United States. Checking procedures in other countries may be different.
Fresh:
Fill basin with water and mild soap or special veggie wash (such as Tsunami 100).
Note: When using soap, use only a food grade cleanser that meets all federal, state, and local regulations. The water should have enough soap to make it feel slippery.
Soak strawberries while agitating the water.
Rinse strawberries under a stream of water.
It is preferable to cut off the top together with a small amount of the flesh.
Strawberries may now be used.”