I have a pair of ProAcs in the Yew finish. Try simply applying some Pledge (Extra Moisturizing w/lemon oil) - available at any grocery store. Spray it on a clean cloth and then apply (DON'T spray right onto the finish). Apply it liberally, but carefully (careful to ONLY get it on the veneer, not the hardware, any matte finishes, or, especially, the drivers/tweeters themselves). Let it soak in for a week. Reapply. It does a great job of conditioning the veneer (mine was starting to get a little crackly-looking around the knots in the finish) and it will slowly darken the finish slightly, but more uniformly after several applications.
It's inexpensive, and it won't (in my opinion and experience) hurt anything. It's not waxy either, so no discernible buildup.
It's inexpensive, and it won't (in my opinion and experience) hurt anything. It's not waxy either, so no discernible buildup.