A friend of mine in college said that Kosher for Passover certification was nonsense. She knew this because her grandfather owned a little corner store and the day before Passover a rabbi would just come in and put stamps on things that said it was Kosher for Passover.
Actually, this is not as much nonsense as it sounds like. Milk and eggs do not require any special certification (for Passover or year-round), but for Passover, they need to be purchased before the holiday. But it doesn't matter when you pay the money, it matters when the product was on the shelf and out of the animal and out of the processor's hands. When you buy milk and eggs in the store, you have no way of knowing when they got on the shelf. Unless a trustworthy source like a rabbi comes in before Passover and marks the things that were there at that time!
So milk and eggs are easy to get for Passover and are a great source of protein for vegetarians (obviously not vegans). The only problem is, you have to get your whole eight days of eggs and milk before the holiday starts. If you run out, you can't buy more (unless a rabbi conveniently marked it). But if you buy too much... milk and eggs don't last forever, and you don't want to waste them!
I have learned a couple of tricks to extend the useful life of milk and eggs after Passover, so you don't have to worry about buying too much! This post will share those ideas.
Homemade Yogurt
Yes, you can make your own yogurt with leftover milk! In fact, the whole point of yogurt was to extend the life of milk at a time when there were no refrigerators! You can make yogurt when your milk first starts to get a little sour (don't let it go too far!) or any time before that. You could actually even make yogurt DURING Passover, but you need a small amount of starter yogurt, which would have to be kosher for Passover.
All you need to make your own yogurt is your leftover milk and a few tablespoons of plain yogurt (with live, active bacteria) for a starter! Basically, you just heat it up to remove any possible contaminants, let it cool down, add a little starter yogurt, seal it up well and let it sit overnight in a warm place. I usually put it on top of a heating pad at its lowest setting. I've also seen recipes that put it in an oven, preheated but then turned off overnight. This link gives you a nice recipe for the oven version:
This oven recipe worked well for me the first time I tried it, but I had less luck the second time. I'm not sure what I did wrong. I've had more luck with the heating pad, but the oven recipe also worked for me once.
The yogurt will be good for at least a couple of weeks, which gives you more time to use your milk without wasting!
Pickled Eggs
If you have leftover eggs, you can pickle them! Again, this is an ancient technique to store eggs before refrigerators, but it works very well in modern times and I have had pickled eggs last for six months to a year (in time for the next Passover!)
This is very easy to do. Before the eggs start to go bad, hard boil them and remove the shells. While the eggs are cooling, prepare the pickling brine: vinegar, water, sugar, salt, garlic, onion and some pickling spices. After Passover I just use store-bought pickling spices but there are recipes online for making your own. Again, this is something you don't want to do before Passover ends because a lot of common pickling ingredients are kitniyot, traditionally forbidden for Passover, such as mustard seeds and coriander seeds. Then just stuff the eggs in a container (I usually use a quart sized Mason jar for 6 eggs) and close it tightly. Let it sit for a couple of days to absorb the flavors. Once it's ready you can keep it for months. The recipe below says only weeks but I routinely keep them much longar than that. In any case, it definitely extends their life.
Here is a simple recipe for making your own pickled eggs.
Have a zissen Pesach, a sweet Passover!
And buy plenty of eggs and milk, because you never know how much you're going to want! You can always preserve them if you don't use them up!