While we are on tooth care, I use a Water PIK to wash models before I paint them. It quickly removes sanding grit, loose putty, etc from panel lines, door seams, and other hard to reach places.
I work in a research laboratory (see alias) and there a lot of specialized tools that I have adapted from the lab to the modeling bench. I used Parafilm long before it became available outside the lab. Weighing spoons, tiny spatulas, and other lab tools make great applicators for putty, epoxy, and various glues. My rule of thumb is that almost any strange lab implement has some sort of modeling use.
We have a vacuum coater for our electron microscope that deposits a gold coating on samples. Sometimes I will stick a small detail part in with the samples and have a perfect gold coating.
I don't know if these qualify as weird tools, but one thing I love about the hobby is scrounging around, finding outside-the-box uses for new tools, and even building my own tools when necessary. If only the quality of my models reflected this effort....