Liability for tax incurred on the use of an article is not extinguished or reduced because of any subsequent sale or lease of the article even if such sale or lease would have been exempt if the article had been so sold or leased prior to use. If a manufacturer, producer, or importer of an article incurs liability for tax on his use thereof, and thereafter sells or leases the article in a transaction which otherwise would be subject to tax, liability for tax is not incurred on such sale or lease.
26 C.F.R. §48.4218-3