When last we met, we were talking about edible gels (or gel like materials) - cupcake frosting, and also cream cheese, peanut butter and other delicious foodstuffs. But not all gels are edible. A great example of the inedible sort, but one that also appears to be highly desired, is Du Pont Advion Cockroach Gel bait. I say highly desired as 13 tubes of it were reported as stolen over the weekend from the Manchester City Hall. Apparently nothing else was stolen, so either the thieves have the mother-of-all cockroach infestations in their homes, or they have some other nefarious activities in mind, although I can't imagine what.
If I had a cockroach problem, I'd gel up some linoleic acid. It's a very effective repellent - it's actually a necromone ("death hormone") that crushed cockroaches give off as a warning to others. So in other words, this cartoon drawing from the cockroach world is pretty unrealistic:
The active ingredient of a linoleic gel is not only non-toxic, but also an essential oil for humans. However, despite all these advantages, you still wouldn't be able to take more than 3 ounces of this gel on a US plane.(Ever seen a cockroach on a plane? I can't imagine that they aren't there.)