Hi judoalex,
The field of neuro-linguistic programming has a lot of good techniques for dealing with unpleasant memories.
A good technique for doing this is the swish pattern. Here are some descriptions of this technique:
The Swish Pattern The Swish Pattern by Tim Mackesey The Swish The NLP Swish Pattern
This book also has a lot of great techniques:
Amazon.com: NLP: The New Technology of Achievement: Books: NLP Comprehensive,Steve Andreas,Charles Faulkner