The Iron Cliffs Company drafts are well known in revenue collecting circles, most notably for their aesthetics and the wide variety of 1st-3rd issue revenue stamps that can be found affixed.
Mike Mahler wrote extensively about a find of these in the November-December 1995 issue of The American Revenuer:http://tar.revenuer.org/TAR1995N10.pdf
I've seen numerous examples offered both online and at shows, and have a couple in my yet-to-be-processed piles.
However, until last week I had never seen one that had an illegal usage of a postage stamp as a revenue. It was offered on eBay at auction at a fairly steep opening price. It ended with no bids, so I contacted the seller and asked if he was willing to entertain offers. I'm glad I contacted him when I did, as he said he was about to ship it off with some other items to a traditional auction house. I made an offer and it was accepted.
It is a June 28, 1869 time draft with a 2-cent revenue imprint (RN-B1) and a 10-cent Washington (Scott # 68), with the added bonus of being tied by an Iron Cliffs blue oval handstamp cancel.
Very few illegal usages are ever found with handstamp cancels. Most illegal usages tend to be from smaller companies in remote locations, and thus would have not gone to the expense of having a handstamp prepared. Of the several hundred Civil War-era illegal usage documents in my collection, I doubt that more than ten have handstamp cancels.
I was originally perplexed by the payment of 10 cents tax in addition to the 2 cents tax paid by the RN-B1 imprint. The correct rate for this transaction is 10 cents, so only 8 cents would have been required in addition to the tax paid by the imprint, not 10 cents additional.
Doing further reading, both Mike Mahler (TAR, January 1988), and either Ben Czech or Ron Lesher (TAR, May 1992; it's hard to tell who to attribute this to as the former is listed as the author at the beginning of the article, but the latter is named at the end of the article) state that every example of Iron Cliffs drafts they had seen, for whatever reason, ignored the tax paid by the revenue imprint and paid the tax in full via adhesive stamps.
I contacted Mike last night, as he had maintained a detailed census of the Iron Cliffs documents, and asked whether he had encountered any other illegal usages on Iron Cliffs documents. His answer was that this is the first one recorded.
A very nice addition to my illegal usage collection.