(note: this is old, from when I was still using Nivea Soft and Olay Total Effects! I soon found out I was allergic to the latter. Ugh — I hate revamping my skincare routine!)

For: a roadtrip, a DIY facial at a friend’s place, a one-night stand. (Oh yes, the latter is so likely planned.)

Start with your daytime and nighttime moisturisers and an empty (clean!) contact lens case.
Scrape up product from a tub with a cosmetic spatula, in a wheel. Sure, you could just scoop it up – but then you’re left with a whole lot of ugly.
If you’ve got a pump- or squeeze- style container, pump or squeeze some into the other side. Drop the case gently from about an inch off the table to help it settle!
Finally, attach the darker lid to the night cream, or draw on some sort of symbol to signify which is which – perhaps a moon with some stars?
That’s all! In no time flat, you have moisturiser that can get through airport security, won’t leak, is much lighter (and smaller!) than bottles or tubs, and that will last you about a week, depending on what you use and how much.