Just a simple trick I used in a recent video. Works best on supers. Put a short fade, say 1 second at the end and add the Gaussian Blur FX. Use keyframes to keep the GB at 0 until the start of the fade and crank it up to Extreme at the end of the fade.
Sorry if it seems a trivial idea but thought I'd post something more in line with what this forum's really here for :)
Bob.