I just completed such a project on a Tayana 37...
1. get a carbide bladed scraper - much better than continual resharpening a steel blade.
2. apply a chemical stripper, but leave it ''dry'' somewhat before scraping. The Cetol will slightly re-harden but will be ''lifted'' and if you ''spill'' it to adjacent surfaces, it wont cause destruction if you can brush it off quickly.
LIghtening teak: --- after all the cetol is removed, sand smooth, then soak with Trisodiumphosphate -TSP, thoroughly rinse with clear water, use several applications of oxalic acid... rinse well again. Then.... if weather permits (no rain) allow the teak to soak up the sunlight UV, cover at night with plastic, etc to keep dry. Alternative is to cover with very thin clear plastic and wait a week or so. The UV ''soak'' after oxalic acid bleaching will give you the lightest color - but usually isnt all that necessary.
If the teack deck has been slathered with cetol (arrrrrgh!), use a bronze wire brush to remove it from the grain after soaking with stripper.
- hope this helps