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I am a collector of United States postage stamps, and also a stamp dealer. I`m a member of the American Philatelic Society (APS). My principle area of interest and expertise is in United States Stamps.

Experience in the area

I've been selling stamps on the internet since early 1996. I maintain a stamp web page that concentrates on mint US stamps issued generally between 1890 and 2009. I'm an active seller on since 1996, under the user id "mleon". You can find my web page at


I have a Bachelor of Science degree in computer science from the University of Nevada at Las Vegas, 1984.

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    K = Knowledgeability    C = Clarity of Response    P = Politeness
Brian02/10/17101010Thank you kindly sir
steve E01/27/17101010Thanks Mark. I had no idea. They .....
Elizabeth12/09/16101010Thank you for your time.

Recent Answers from Mark Leon

2017-02-06 Rare perf franklin??:

Brian,    I've never heard of the 30 cent Franklin issue perforated 11-1/2.  I recommend showing the stamp around at the next stamp club meeting in your area.  See if others concur with your measurement

2017-01-26 stamp:

Steve,    The $5 and 50c dated 1953 red documentary revenue stamps you describe are designated Scott numbers R642 and R630 respectively.  In used condition (but otherwise fault-free and eye-appealing)

2017-01-10 Jefferson Memoriual Booklet:

RP,    That's puzzling.  When I think of frameline, I imagine a thin line surrounding the design, which does not exist on the 1973 Jefferson Memorial issue.  Even the booklet covers have a solid background

2017-01-10 MLB Plate stamps:

Janella,    My expertise is limited to United States stamps only, so I cannot speculate on the resale value of your Grenada issues.  I've never heard of the International Collectors Society, but I suspect

2016-12-16 13 cent preprinted postage envelopes Bicentennial:

Andy,    Unfortunately, stamps from the 1970's have not appreciated in value, and most sell for below face value in quantity.  The stamped envelopes you describe, called postal stationery, are still valid


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