If it’s liquid, and likely to spoil before you can eat it all, why not get it to go into ice cube trays. Take homemade pesto, something that you only need a teaspoon-or-two at a time make it last forever.
Spray a plastic ice cube tray lightly with nonstick cooking spray. Spoon in the leftover pesto into the holes, make sure to leave a little of room for expansion. Stick the tray in the freezer and let the freezer work its magic.
After the contents are frozen solid, remove the tray and pop out the pesto cubes. Stick them into a freezer-safe plastic bag, label, date and place back into the the freezer.
When you are ready to use anything you freeze take out what you need and thaw at room temperature in a dish (unless you plan to toss it while you are cooking and you could skip this part).
You can use this technique with homemade sauce, hotdog chili, cooking wine (not drinking wine) and many other things that you would make from scratch in terms of sauce. Let me know how this goes and post your comments about your adventures in ice tray cube sauces!