I'm often dubious of "helpful" hints that one finds from various sources to solve day-to-day problems. Perhaps this stems from watching my mom experiment with tips gleaned from Readers Digest in my youth (Cayenne pepper in one's socks to warm one's toes comes to mind -- when it didn't work immeidately, she added several more spoonfuls and headed off shopping, at which point her feet started to sweat, and then burn. Her toenails were orange for weeks.) Or perhaps I'm just suspicious of unverified data in general.
But, to be fair to my mom and to helpful hints in general, once in a while something actually works. Shaking Polly Pockets's evil tight rubber clothing in a bag with some cornstarch does indeed actually make it possible for a kid to then slip them on the doll without having to ask for help. The hot water/baking soda/aluminum foil dip for silver does really instantly remove tarnish.
At any rate, the occasional success led me to search for a relevant hint after we discovered that the car was covered in pitch from the tree it had been parked under during our Monterey bike trip. Said pitch has splatted all over the windshield and side of the car, my haphazard hurried wipe job did very little good, and the week and a half since the goop deposition has been both busy and warm enough that the substance had turned into a hard crust of seemingly impervious crud. Good old soap and water wasn't going to do it.
A quick web search turned up a variety of suggestions, some involving icky chemicals I didn't want to purchase, others making me worry about the integrity of the car paint after the process was done. One suggestion struck me as both cheap and plausible -- try putting some vegetable oil or shortening on it for a few minutes, then wash the whole mess off. The theory is that organic vegetable goo is likely to dissolve in other organic vegetable goo. Or perhaps the oil just wicks into the interface and loosens it. Quite similar to the old "Use peanut butter to get gum out of one's hair" trick (used many times in my youth, I have to admit).
On the glass windshield this worked just like a charm. Put shortening on, wait 10 minutes, wipe the whole mess off with a soapy sponge, and rinse. No scrubbing. Amazing.
On the car body, it wasn't quite as easy. The pitch softened up a bit, but still required quite a bit of scrubbing and rubbing to get off. I'm studiously not thinking about differences in interface adhesion of pitch on glass vs. on car paint as it reminds me far too much of organic thin film adhesion problems at Allied Signal....