Personally, I would avoid the WD-40 altogether. Clean the gun as you would a muzzleloader - hot soapy water, very hot rinse - then blow it out with a high pressure air hose. Lightly oil with break free. Give thanks for the recovery. There is a Winchester Model 12 at the bottom of John Martin Reservoir that got there the same way as your rifle did - after eleven years, there probably isn't much to "recover" even if someone did find it - and return it.
