Tips for removing an agarose overlay

Have you ever done a viral plaque assay that requires an agarose overlay and wondered how to remove the overlay without disrupting the cells below? Sure you have. Here's my method:

1. After seeing plaques in your cell monolayer, remove media and add 2 ml (per well of a 6-well plate) 1% formaldehyde/PBS to your agarose-overlaid cells. Incubate overnight at room temperature. This will fix your cells.
2. Remove formaldehyde, rinse wells with water.
3. Use a squirt bottle to squirt water along the edges of the well. This will loosen the agarose. Invert the plate over a biological waste bin and continue to squirt water into the well, while giving the plate a tap or flick. The agarose should slide out of the well and into the trash, leaving your cell monolayer unscathed.
4. Stain cells with 0.05% Neutral Red (or Crystal Violet) for a few hours, or even overnight, wash with water, air-dry the plate and count the plaques.
5. Viral titre (PFU/ml)= number of plaques/(dilution factor)*volume of diluted virus added to the well.

It took me a few attempts using other clumsy methods before stumbling on the squirt bottle trick. It's a method I haven't seen online anywhere so hopefully this will be helpful to a fellow scientist. Happy virus culturing.