will clear every graphical and otherwise objects in the program except vars.
You can also manage and free your media without terminating the graphics.
It is good practice to free your memory as soon as you don't need an entity, a sound or an image anymore, expecially if you are loading heavy files which would eventually fill up the available RAM and VRAM.
Take a look at all the commands with the "free" prefix, such as (but not limited to) 'FreeFont', 'FreeSound', 'FreeEntity', 'FreeImage', 'FreeTexture'.
Also, be sure to clear unused types which you don't need anymore by using the 'delete' command only *after* freeing all the fields in it, or the content will stay in memory but you won't be able to access it anymore.
In order to elude stuttering and pauses avoid to manage your media during gameplay, too.