What should I do with ex’s love letters?

Me (26m) and my ex (24f) of 1 year broke up like 3 weeks ago. The situation kinda sucked but the breakup was clean, wished each other well, etc. long story short she lied to me about few things in the beginning of our relationship and I held on to that, then ended up doing something I wasn't supposed to. I lied to her about it until she found out elsewhere. We tried for a while after that but it wasn't working. By all means she was a little crazy, cut herself in front of me, got the cops called on us once when she got upset (no one was arrested). Anyways, I really did love the girl and she absolutely adored me. Breakup has been kind of rough, I got so used to her familiarity and of course I miss her. She wrote me tons of letters in the last year, probably like 15. I'm not sure what to do with them. Idk why I'm holding on to them either. Idk what she did with the ones I wrote her. Idk if I should throw them away, keep them, why would I want to do that, idk