Again, not really except buy a new PSU. Take the opportunity to get one with a greater rating, such as 750-850W, as this will allow you to upgrade your system in future (better graphics card, etc).
Consider it a lesson learnt, albeit an expensive and potentially dangerous one.
Remember when cleaning dust and other detritus from computer hardware to only use a can of compressed air. Never use anything liquid-based, such as WD40 or the stuff you used (even if it does evaporate). There is no telling what damage the contained solvents could do.