what did you use to wash the mirrors? any possibility its left some very fine residue on the mirrors?
If the secondary shadow is slightly off center, take a look down the aperture of the scope and see if the secondary is well centered in the tube. If not, adjust the spider vanes (via the 4 thumb screws on the outside of the tube, then re-collimate...
Is the blue flaring off to one side? or the whole way around?
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