Pacemaker Boat Owners Association

It sounds like you need to restore abused teak rather than just refinish.

Both Mequiars and Starbrite have a 3 step cleaning/finishing system (the third step is teak oil). You can get this from eBay or Amazon.

The first step cleans the wood; the second restores; and the third finishes. You only have to brush or wipe the teak oil once yearly to keep the look (the first two steps are restoration of damaged wood).

I've used both systems (including mixing and matching) with excellent results. I just restored my swim deck on my '69 Alglas, which looked like it NEVER was maintained); and - so far - I can't believe the results.

Start with Te-Ka 2 part teak cleaner.
Some people go the teak oil route (Amazon teak oil is personal favorite for oil).
I personally love the look Deks Olje produces. It is not cheap but if you do multiple coats according to the directions of both the #1 and #2 it really comes out nice. http://www.jamestowndistributors.com/userportal/show_product.do?pid=168&engine=adwords!6456&keyword=deks_olje

Stay away from Cetol