Newbie question - Mortgage lien status after foreclosure

[Jay Wood]

What happens to a mortgage lien after foreclosure at county auction?  Example with simple math/numbers - if Wells Fargo Bank has a $75,000 original note, remaining balance is $60,000 and it goes to foreclosure/auction on the steps of the courthouse, auction brings $35,000, what happens to the $25,000 difference?  Does the winning bidder 'inherit' the amount?  Does it disappear?  Is the property clear of that lien after foreclosure?