gfever, if he develops a phobia of something important, deal with that. For example if he becomes terrified of dogs, or bath drains, or things you run into in your daily life, that needs to be dealt with.
This kind of seems silly. Throw the stupid thing away. Better yet, allow him to decide how to destroy it for good and ever.
I agree with the first reply - just throw the toy away (and my reply is even shorter).
Please more replies. But I want replies that are long and have good advice. Also, please read through my post carefully.
I would just throw the toy away. A lot of even non-Asperger's children develop strange phobias during childhood--even with familiar objects/places--like the shower.