Let me revise my question below. What are you using to store you fresh chopped lettuce in.

How are you all keeping your lettuce fresh for a couple days ??? I absolutely do not like the pre chopped & bagged stuff. For yrs I have been buying my own iceburg lettuce & romaine, chopping & mixing & storing in plastic container. We use a ceramic knife to chop as well, but like Sunday we chopped lettuce for the next couple days & this morning 1 tub was already turning rusty looking, just tired of tossing out every few days

what I do for my ceasar salads is this.
I have an 18 quart cambro that I fill with chopped Romaine. I Fill it with cold water. At the start of every day I use a small salad spinner and spin out (twice) enough Romaine to fill about 8 ceasar salads.(I add shaved parm and croutons when theyre ordered) I leave the remainder submerged in the cold water in the walkin cooler. Its not the most ideal, but it works well for us. I do the same for shreeded lettuce but I keep that in a five gsllon bucket

We clean our Iceberg lettuce. Chop it all up then put it in a 5 gallon bucket. Fill it with water. For the evening we will drain what we think we will need. If we do not use it, it gets watered again for the overnight.
Mind you on the days we clean it, we keep out what we will use and do not cover it with water. Saves a ton of throw away brown lettuce.

Back in the day the cure to that was to add a sodium metabisulfite to keep things from oxidizing, the current anti-browning additive method is based on citric acid.

Take a look into it, see if you notice a difference, and it may save you a few bucks over the year

I thought they took that off the market yrs ago???

Sodium metabisulfite was removed from use, it was replaced with citric acid based compounds.
Some lemon juice in your rinse water may achieve an anti-oxidizing effect without too much flavor change