S and Forgetting

I was very intrigued by Luria's description of S.'s attempts to forget things. Though the methods S. tried to use to forget information he no longer wanted to be able to remember seemed odd and rather tedious at times, such as having to take time to visualize burning the information, it does seem to fit quite logically with S.'s general patterns of memory. When he would hear something, such as a sequence of numbers or words, he visualize the information in a chart and, when later asked to recall, would retrieve this information from his visual images of these very same charts. When he would try to forget this information then, he would visualize a chalkboard with these charts and attempt to mentally erase the information---another visualization technique. It was surprising to me, then, that such a method did not work. The fact that he found success in a method as simple as not recalling things he did not wish to recall seems unusual, and left me with an unanswered question. Though in one instant, such during a performance, S. might not wish to remember certain data and is able to "forget" it, does that mean he will has forgotten the data forever or just in that instant when he wanted to forget it? If he later wanted to remember data he had previously "forgotten," would he be able to? I am hesitant to believe that a man with such a complex and detailed memory system to rid himself of memories in such a simple and passive way.