What I have done with several knives is just to grab the clip and bend it outward.
Now, you have to exercise extreme caution, because its easy to bend it too much. So what I do is just pull it 10x or 20x times, but not enough to actually tweak it. Just to get a feel for it. And then start to pull it multiple times with very slightly more force, but still not bending it. If you are mighty careful, you can bend it just a micron, so that the clip is just barely looser then it originally was. I like for my clips to have the absolutely smallest amount of space between the clip and the scale.
This is dangerous, because its easy to bend it too much. The only solution for that is to remove the clip, bend it back to its original tension, and then start over. But without tools that's a no go. But after you get the hang of it, its not really that difficult. You just have to very, very carefully apply very small, increasing amounts of force to the clip until you achieve the desired tension.
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Your best bet is to buy a quality torx driver of the right size, then remove the clip and sand under it. Having the right torx driver makes it much easier to get the clip tension just right as well. You can get a mediocre torx driver set at Home Depot, or a quality driver online. Rock on.