IMHO, the reason one feels “pure” while in school is not just because you haven’t done anything wrong yet, but rather because your neshama is constantly being “cleaned” with the continual input of Torah and Hashkofa. This immersion in Torah and Hashkafa is what keeps you feeling pure. But once you leave school this input is stopped, and things go downhill from there. (As the Baalei Machshavah tell us, a person is never standing still; they are either growing or falling.)
Therefore, the logical way to gain back this sense of purity is to re-immerse oneself in Torah and Hashkafa.
(On a practical note, I highly recommend the sefer “In Their Shadow”, a collection of truly inspiring Gedolim stories that show Hashkafa in action. After spending just a few minutes reading these stories, I can literally feel the difference… it really helps add that spiritual sense to my day.)
mdd:
“some of the so-called right hashkofoa are actually farfrumed ones. Even if I accepted what you wrote about the right hashkofos and right sources as is, still, this is not something to lose sleep over.”
This statement is a perfect example of what adorable was referring to (wrong hashkofos on the internet)… Losing one’s correct hashkofos is most definitely something to lose sleep over.