After cleaning the injector overnight in solvent, the engine still didn't
fire on the one cylinder. My mechanic talked about the rope trick as well,
but I didn't catch the whole process.

How does it work, and is it something that can be done without a lot of
expensive or unique tools?

My mechanic (not based at my home airport) is coming down next week to work
on the plane, and he assures me he has lots of spare valve cover gaskets, so
I'm going to pull the cover off today and see if the valve actually works.
If it's not too complicated I would like to try the "rope trick".

Any recommendations on stock (cork) versus silicone valve cover gaskets?

TIA