You would need to contact the lien holder and determine the amount of the debt.
You may also get some additional information - such as the reason of the lien, was the lien a result of a judgment, is there any statute of limitation for that type of lien, the amount of actual lien, interest and penalty, if there is any option to settle the lien, etc.
The only way to obtain such information - to contact the lien holder. You may find the information about the lien holder in your county where the property is located and the lien registered.
If that was an IRS lien that was settled - you need to contact the IRS for the lien to be removed.
Let me know if you need any help.
TITLE 26 > Subtitle F > CHAPTER 64 > Subchapter C > PART II > § 6325. Release of lien or discharge of property - http://www4.law.cornell.edu/uscode/26/usc_sec_26_00006325----000-.html
The IRS is required to issue a certificate of release not later than 30 days after the back tax debt has been paid in full or the tax debt becomes legally unenforceable because the statute of limitations for collection has expired.
If the IRS did not do that timely - to resolve the issue - you may just walk-in your local IRS office and ask them to issue a certificate of release. No appointment needed.
Let me know you state and I will provide you contact information.
Tax Preparer
Taxes, Immigration, Labor Relations
Generally - the statute of limitations on collection is 10 years since the tax was assessed.
The statute of limitations can be extended by agreement between the taxpayer and the IRS provided the agreement is made prior to the expiration of the 10 year period.