One good tip deserves another...
Chuck W., a very good modeller who once posted here advised using the broken UMM and similar blades to make small saws like the one's Pawel pictured above. The blades are naturally brittle, and will fracture sooner or later; you can shape them further with pliers (eye protection please!). Any small handle will do - I use wooden dowels, cutting a slot and CA glueing the blades in for handy minisaws. They're great for tight spots and for cutting delicate parts from sprue.
I'm going to try Pawel's idea as well - I've got a few single edge razor blades in the toolbox.