What do you do if the IRS put someone else's lien on your house?

Your question is unclear because it doesn't happen that way unless the owner of the house got it from the delinquent taxpayer after a lien was filed and didn't do anything to get it off. IRS will file a Notice of Federal Tax Lien that attaches to all of the taxpayer's property or rights to property that doesn't say it attaches to anything specific except in very odd situations. The lien will state the last known address of the taxpayer but that doesn't mean that the lien is on that property.

Since the lien was done before 1976 - then the 'someone else's' name is who owned it at that time.

If you purchased the house (after 1976) then the one you bought it from should have paid the lien

off or they could NOT sell it.

Details. If you really have clear title to the house, that wouldn't happen.

Shouldn't have happened

Should have been letters, title search

Call Taxpayer Advocate now

this might require real legal assistance, doesn't have that much to do with taxes as it does incorrect charging of tax debts--IRS isn't always right

Write a letter. keep a copy of all correspondence related to this matter; for this sort of thing you need a paper trail.

you contact them and try to clear it up - gather all the info you can from when you bought the house

You call them and you work it out.

Ask them to change it.

call them