Jill’s got a smart method for untangling marionette strings:
We have a cute dragon marionette around here, but he’s chronically tangled. I just undid his knots for (I hope) the last time. I cut the strings off at the top by the wood handle. Instead of tying the untangled strings back, I tied each end to a pony bead (1/4″ bead) led it through the slits of the wood and let the bead hold the strings on. Now I can completely undo the strings to untangle the puppet. Mine had slits in the four ends of the wood sticks where the string went in, but these could be cut pretty easily.
Related: Homemade finger puppet stand