[magsmaggie]

I have mysqld setup to handle the kodi database so I am wondering if it is safe to remove the contents of ~/.kodi/Database/*.db

A related question is what about ~/.kodi/userdata/Thumbnails which is HUGE for me. Thank you in advance for my newbie questions.

[Gombeek]

as for thumbnails here is a tool made to clear that folder.
https://www.youtube.com/watch?v=aHDlXYV9EG4

[graysky]

@OP - Why not just stop kodi, backup your mysqld, move that dir to another name, and restart kodi? See if something is broken without them. Also, you can use CLI solution to clean thumbnails: https://github.com/MilhouseVH/texturecache.py