Whether you are an ASCC member or not, ASCC encourages to proudly exibit checks from your collection!
The appropriate venue for exhibiting your checks depends upon the focus of your collection.
For example, if you focus is on documents with revenue imprints or affixed revenue stamps, you may consider an entry in a stamp show. The American Philatelic Society (APS) website lists national and regional stamp shows. A link to this website may be found on the Web Resources page. Note that this list may not include many local stamp shows. Most of those can be located using Google®.
Even non-stamped checks may be exhibited in a stamp show as a display only (non-competative) exhibit in local shows.
Paper money shows may have exhibits of checks, and should be explored as a possibe venue.
Other venue options for exhibits are historical societies and libraries, and any other venue you deem appropriate for the collecting interests. Be your own promoter of your exhibit!
Guidelines and format examples for exhibiting in stamp shows are available on the American Association of Philatelic Exhibitors (AAPE) website. A link to this website may be found on the Web Resources page.
Another way to "exhibit" your checks is to write and submit articles for publication in the ASCC publication, The Check Collector. Help may be found on the Submitting Articles page.
Organized shows which encourage exhibits should have adequate security for the exhibits, but if in any doubt, inquire. Post offices, banks, libraries and the like may or may not, so beware.