Use your heat gun. Heat the monokote, but hold he gun about a foot away. This will melt the glue without shrinking the covering. Now with a hobby knife or something else, pry the edge up and just pull the seam open.

You may want to wear a gove on the hand that is working infront of hte heat gun.

While a hair dryer is not hot enough to shrink monokote, it probably is hot enough to release it so you can reopen the seams.

[8D]