Several weeks ago, I bought a pair of lime-green AME lever hoods from Hilary Stone, who had described them as "grubby." They arrived promptly, exactly as described (Thanks, Hilary!)
So, what to do about grubby brake lever hoods? One product I have found useful is "liquid rubber buffer," which can sometimes be found at better auto supply stores. It is what tire repair folks use (or used to) to chemically clean inner tube surfaces before applying the glue. I keep some around for that purpose (works better than sandpaper when available, leaving a really well-prepared surface). If I had a bike shop, I think it would be faster and more mechanic-proof than sanding (if anyone still repairs flats instead of replacing tubes).
It is doing a decent job on the lever hoods, too. Think I paid about $10 for a quart some years ago; last me years and years.
Your mileage may vary.
harvey sachs
mcLean VA