Another way to remove a lien, is lien subordination. This allows a creditor to “subordinate” the IRS interests in a property and move the process along. The IRS will only allow this if you pay them sooner.
An example of this would be: if you are trying to refinance your home; the IRS will allow the lender to go above the lien and refinance as long as the IRS gets a portion of the profits.
This process can become very complicated, so as always; professional assistance is recommended.