I had intermittent, and then consistent starter malfunction due to loose
wire connection at the starter.  (Digitool showed starter circuit power
as normal.)  After reaching with my hand from above to manipulate the
wire connections on the front of the solenoid, the starter resumed
function.

I'd like to remove the wires and clean, but I cannot imagine removing
the wires without first removing the starter.  Is that the only way.
Bentley shows tests, but does not clarify access or removal before
testing.

How much time might I have before I need to jiggle the wires again, or
fix it with a proper cleaning?

Thanks, David-looking-for-a-vanagon-expert-mechanic-in-San-Antonio