Roland, there is no totally safe method for removing paint but there are chemical strippers that are relatively safe. I would use a stripper like Peel Away 6 (see www.peelaway.com) or Citristrip (see www.citristrip.com). The websites shown will give you more details on the products.
The problem with a heat gun is that it can get the old paint so hot that lead will vaporize. This is not good. Neither a chemical stripper or a heat gun will allow you to strip off just certain layers of finish. Let us know if you have further questions.