Homemade variations are typically square, round, or triangular; the bread can vary, e.g., white or whole wheat; and the sandwiches can be homemade with common crimping techniques similar to pie crust, ravioli, or dumplings using readily available kitchen tools (e.g., a fork, small spoon or curved knife end to crimp the edges).

The sandwiches offer easily-frozen and thawed, ready-to-eat, portable convenience and have been called, "the Swiss Army knife of foods".

[4] In the United States, mass-produced crustless sealed sandwiches were introduced in 1995, in Fargo, North Dakota by David Geske and Len Kretchman[7] — at the time marketing as Incredible Uncrustables to schools in the Midwest, with fifty employees making roughly 35,000 of the sealed sandwiches daily by 1998.

In 2023, Smucker said it took about ten years to prevent "leaky sandwiches," designing the bread so it doesn't create air pockets and using round loaves.

[17] Smuckers, with $7.8 billion in net sales as of 2020, has issued cease and desist letters to any company marketing crustless sealed sandwiches in a round shape, including small businesses, arguing trademark infringement.

Targeted companies have included Chubby Snacks,[7] which revised their sandwiches to a cloud shape; Albie's Foods[7] which revised their EZ Jammers to a triangular and later square shape, and Gallant Tiger[18] which markets a decidedly adult-flavored product (e.g., chai spiced pear butter and peanut butter) selling at a price-point roughly six times the cost of an Uncrustable.

These included a 1949 patent (U.S. patent 2,463,439) that described a device to create these types of sandwiches: "An object of this invention is to provide... a means for locating said filling in the center of the sandwich and sealing the marginal edges of the pieces by heat and pressure to preclude the escape of filling from the finished product... [and] a means for trimming the baked dough pieces".

Instead of capitulating, Albie's took the case to federal court, noting in their filings a pocket sandwich with crimped edges and no crust was called a "pasty" and had been a popular dish in northern Michigan since the nineteenth century.

In response to the new prior art cited, Smucker's narrowed the wording of their claims to only cover a very specific version of their sealed crustless sandwich.

Because Smucker's failed to respond to the Board's rejections within the two-month deadline, the PTO mailed a Notice of Intent to Issue a Reexamination Certificate (NIIRC) in December 2006 cancelling all claims.