There are two places you will need to delete cache when it becomes full.
1.Deleting your CACHE before entering into kodi is key for best performance. How to delete CACHE: go to settings > select application> select manage application > select KODI > select delete cache> select launch kodi.
(A warning about the cache filling up does not actually mean that more cache space is needed or that the existing cache needs to be emptied. The warning box is not currently well worded and has lead to a lot of confusion with users. What it means is that the video is loading too slowly for the cache to smooth out all of the bumps, and that the bumps will keep happening due to that low video speed. No amount of video cache tweaking will make a slow server connection any faster, which is a common issue for people who stream over the internet. Even if you have a fast connection on your device, it doesn’t matter if the connection on the other end is slow. The server itself might not always be slow, but might be more busy at different times of the day.)