Have you ever opened a carton of egg whites and the texture was so thick (resembling a thick mucus) that the whites wouldn't even emerge from the carton?
This has now happened to me 3 or 4 times in the last couple months. Some cartons I buy are fine and others are like this. The cartons are each well before their sell-by dates. They are all from the same Safeway, all of the same brand, and I'm storing them in the same part of the fridge. So, I'm not sure if they're coming from Safeway this way or if they're getting this way while in the fridge.
Welcome to DC! I know nothing about purchased egg whites...mine come in the shell. However, I do that in Canada eggs are stored in a temperature controlled warehouse before hitting stores. The "older eggs" that are in storage often go for powdered egg yolks, whites, and egg whites in cartons. I second Kayelle's suggestion. If you don't know what to do with the egg yolks, you can (a) mix a yolk in when making burgers, (b) use them for baking, (c) feed them to your dog if you really can't/don't want to eat the yolks.