Some people will tell you that nose-picking is gross. They will tell you it is unsanitary. They may even make you feel ashamed for doing it. You know what?
At some point, these people have picked their nose.
Face it, no matter what some may say, there are some boogs that just aren't gonna dislodge without some digital assistance. There are some that, despite your best efforts with a sharp kleenex blast, will cling to your inner nostril for dear life. The important thing is to stay calm and remember a few things:
1. For God's sake, whatever you do, DO NOT pick your nose with your pinky. You will look like a complete asshole, or at least a bigger asshole than you already are.
2. You can try the technique being practiced HERE by Brooke Shields. It can be likened to squeezing a tube of toothpaste from the bottom in order to force the remainder of it out the opening. You place the thumb and index finger on either side of the nose and carefully but firmly pull down, hopefully forcing any boogage out without penetrating the nostril. It rarely works and may lead to unwanted suspicion of cocaine use.
I recommend a variation whereby you place the index finger on the side of the nostril and drag the thumb along the base while gently pulling back the nostril edge. If you are smooth about it, it will appear that you are just innocently scratching your nose. Actually, if you are lucky, you just might snag the edge of a clinger in the process and be able yank out a big one without attracting a lot of attention. Again, any penetration should be undetectable. Don't be discouraged if it doesn't work at first. Practice in your car until you get the hang of it.
There will be times when a full-fingered stab is the only solution. Do not feel guilty. It doesn't make you a bad person. Hell, even some of the most respected members of society have to resort to it from time to time.