Cleaning Wool Headlining.
I would suggest a dry foam, either wipe or spray (Valet is a good one). The problem with the wool is two fold. Firstly, on the later models the change from tacks and staples was made to Adhesive and on most wool headlining's where adhesive was used (especially smokers cars) there will be visible marks where it has been applied this is because the lining has been effectively sealed on the inside with the adhesive application. I have not yet seen any cleaner which will get the lining clean enough to eliminate this witnessing. Second, if you choose to use a water based solution, do not soak the lining, it WILL shrink and give you more probs than you bargained for.
Hope this helps. Col.