One popular way to collect Joint Issues is on First Day Covers with First Day cancels from both (or all) participating countries, which would be very difficult, were it not for the policy of most postal administrations, including the USPS, of providing First Day cancels up to a month after the actual issue date. Below is a selection of my favorites. It's no coincidence, by the way, that so many of them are Collins hand-painted FDC's, as he's my favorite FDC maker. I've even created several pages devoted entirely to his work - here.

Click on any image below to view a high-res version

IMAGE	ISSUE	Date	Cachet
	Opening of the St. Lawrence Seaway	6/26/59	Unknown
	Philip Mazzei	10/13/80	Fleetwood
	U.S./Sweden Treaty of Amity & Commerce	3/24/83	House of Farnam
	St. Lawrence Seaway 25th Anniversary	6/26/84	Artcraft
	Centennial of the Statue of Libery	7/4/86	Collins
	U.S. - Morocco Friendship	7/17/87	Collins
	Australian Bicentennial	1/26/88	Ham
	Australian Bicentennial	1/26/88	Collins
	New Sweden 350th Anniversary	3/29/88	Artcraft
	New Sweden 350th Anniversary	3/29/88	Collins
	French Revolution Bicentennial	7/14/89	Encotel (? Argentina)
	Switzerland - 700th Anniversary	2/22/91	Pugh
	US - China Cranes	10/9/94	Carol Gordon
	Hanukkah	10/22/96	Powell
	Hanukkah	10/22/96	Barbara Montgomery
	Cinco de Mayo	4/16/98	Ryan
	Cinco de Mayo	4/16/98	Dynamite
	Cinco de Mayo	4/16/98	Heritage
	Irish Immigration	2/26/99	Barbara Montgomery