Unplated copper spades/banana

Gauge 10 copper wire has resistance of 0.001 ohm per foot. Gold plating is typically 0.00001" thick. It adds additional resistance in order of 1 microohm (o.ooooo1 ohm). Perhaps there are other effects when signal is crossing boundary of two different metals, but resistance of plating is not important IMHO.

Most all wire is copper.  The difference between a gold plate does make a difference, but in the big scheme of things, the difference between a gold plate and naked copper is really really really small. Rather than having to polish the ends on all of my cables, I choose to go with plated ends.

My two cents.

On the conductivity scale, copper and gold are very similar and you won't hear an actual difference with the only useful testing (blind) but bare copper will tarnish and need to be cleaned periodically. 

Copper needs to be cleaned every 6 months or tarnishes  that’s why they are gold or rhodium plated 

I use COPPER spades and use DeoxIt (2 formulas are available, one for copper, and one for gold) and Stabilant 22 clean/condition them  once or twice each year. 

No big deal... 

On the positive side, taking the time to clean the connections gets me back 'into the details' of my system.  I use this time to check my TT parameters, outlet connections, speaker placement, etc.  

I once owned a set of inexpensive, platted speaker cables and learned a lesson -  avoid plating where reasonable to do so.