While it may be a total loss there is a proven method for cleaning up Tek scopes subject to this abuse.
Remove all the tubes including the CRT.
Remove the power transformer and either cover, or better still, remove the HV transformer.
Spray the entire chassis with Simple Green, allow to soak for a while.
Hose it down with preferable de-ionized or distilled water.
Bake in an oven at about 150 F for a few days.
Granted, it's a lot of work and you still might have a basket case. It's a tough call.