When I bought my used '04, the first thing I noticed were scratches (and a few opaque 'blobs') on the tach/speedo display. Looked like someone used some type of solvent, and some dirty rags in an attempt to clean them. I've lived unhappily with it until last weekend, when I finally pulled out the Meguiar's plastic cleaner, and plastic polish. I've used them on my miata rear window, but was hesitant to try it on the tach.
The results were awesome! Used as directed, the scratches all but disappeared, and the opaque blobs went away completely. (Sorry, no before and after pics.)
So if your speedo/tach has gotten scratched up, try some Meguiar's or Novus and watch the scratches disappear. The weren't all that visible when driving, but now it's noticeably clean and clear.:smile:

 

WOW! great post...thanks for the heads up....always nice to hear what people are using and if it works etc...thanks again

 

Nice one. Mine has gotten scratched a bit as well....Will definitely try it out..