I found myself in a sticky situation the other day. I was in full study mode and was hoping to steal some peanut butter from my dining hall. The problem: no container! Well, as it turned out, I did have a container, but it had a bunch of old, expired peanut butter and I didn't wanna risk making myself sick before my Orgo final. So, what'd I do? I poured a dab of laundry detergent into the peanut butter jar with some hot water and shook it. Then *poof*--no more peanut butter in the jar!
You'd might guess that it's simple enough: the detergent just cleaned the peanut butter of out the jar... in that case, you'd be right. But maybe you'd try to use soap. Soap would probably work too, but not as well. So, what's the difference? As it turns out, this is a biochem problem. As anybody who eats peanut butter knows, it is full of proteins. So, to clean out a peanut butter jar, simply break don't all those proteins--which detergent does quite well. Why? Well, the active ingredient in detergent isn't just a really tough soap; in fact, it contains a tiny but potent amount of proteases--enzymes that digest and break down proteins. So the proteases (which are also heat-resistant) break down the proteins, and the hot water washes 'em away.
Hence I am left with a clean peanut butter jar in a jiffy. With that, I am off to steal some peanut butter!