How to remove multiple genre entries from rekordbox memory cache

I'm having and issue with automatic genre incorrectly selecting genre from drop down menu. I use specific genre naming patterns example. Tech-House, Progressive-House, Minimal etc I have removed all previous genre naming patterns, however they still exist in the drop down menu along with every other incorect genre which Rekordbox obtained from tracks loaded into the program prior to correcting the genre example. (Rock, Metal, minimal) a long with various other incorect genre entries made by other people which were downloaded by or ripped from vinyl years ago. Yes, I've aquired downloaded mp3's over the years, however most is stuff that can not be obtained any other way let a lone digitally. Yes, I actually purchase my music as well last time I checked with beatport alone I've spent almost $5000 Us dollars woth so please let us stay on topic with regards to my actual question. I would greatly appreciate any help. I'm also curious in the possibility of Rekordbox implementation of batch editing.
Thank you in advance for your help.