Most microwavable foods say to puncture or open the plastic film, but the instructions on the Kroger mashed potatoes said to leave it on at first.
The 24-ounce container cost $2.50 ($0.10 an ounce), making it the cheapest option.
I placed the container of potatoes on a microwave-safe plate, an instruction I almost skipped and am glad I didn't. The potatoes leaked out a bit onto the plate and would've made a mess in the microwave without it.
I microwaved them as directed for three minutes, removed the film entirely, stirred the potatoes, and cooked them for one more minute. But I think I could've skipped the extra minute (an optional step in the directions).