You can select the files you want to edit and change the field values of the fields you don't want to keep to < blank >. Additionally, hitting [ALT+T] will pop up a window containing more tag fields. Again, tell MP3Tag to delete the fields you don't want to keep.
You can use the Tag - Filename wizard for that. Hit [ALT+1] and type in artist% - %title%.
Maybe, I did not explain well. in my title field, there is...,
title of the song - mp3s
eg.) It's My Life - mp3s
I would like to get rid of all <-mp3s> from the title.
Yes, I know how to do it manually. I have tonz of files in that way. So that, it is painful for me to do manually.
Also, Would it be possible to delete some fields such as comments, by using some scripting?