Can you delete documents from the library on Mac without serious consequences for your computer? When I checked my Mac's harddrive I noticed that it was almost completely filled with files in the category 'other'. I used mac cleaning software to see what files were taking up a lot of space and those were mostly documents with names like: d8434hjk3hj5v3kj
Without any extension. 

Will deleting these folders harm my mac?

Mac specifications:
- Mac OS X Lion 10.7.5 (11G63)
- 21.5-inch, medio 2011

I'm not much of a technology guy so if I need to be more specific please let me know.
I realize you might want a short answer, but in reality, the real question is have you set yourself up with a backup system that works well enough for you to go ahead and experiment and delete these files without serious repercussion.

My feeling is:

You shouldn't delete anything from /System or /Library unless you have a backup and have time and energy to perform a restore from that backup. No matter how good information you have, eventually your instructions, hunch, training or experience let you down and your machine won't work as you need it to.