A couple of weeks ago, I discovered that one of my boys had put some gum in his pocket (already chewed, of course.) The jeans had already been patched and were not worth the time it would take to remove the gum from the pocket to salvage them. However, they were still good pants for playing and camping, so I decided the pocket was expendable.
This is what I did:
First, pull out the pocket.
Second, cut the gum-riddled pocket lining out.
Finally, I did not want him to put anything important to him in his pocket and then realize too late that it no longer had a lining, so I topstitched it closed. I started just under the top rivet and stitched just below the bottom yellow stitching line of the pocket, all the way to the seam. The only thing you have to make sure of, is that everything is smooth and looks normal before you stitch the pocket closed.
This was super simple and only took a couple of minutes, but will extend the life of these jeans by a few months, at least. In fact, it was so easy, that if I ever discover some gum in a pair of good pants, I might do the same with them.
Just a note - - I have a spool of denim colored thread that I use for all of my repairs and patches on my jeans. I find it does a pretty good job (not always perfect) of blending with almost all of the jeans I work on, whether they are dark or really faded.