Alternative way:
The easiest way if those DBs are related to sites here at x10hosting is to go to the cpanel => Mysql DB & locate the DB u want to delete, if that is what u mean by clearing, select it & delete it.
If it is just TABLES as you say, go to phpmadmin, select the DB with the tables u want to delete, select the tables you want to delete, & at the bottom of the page where u are asked what to do with the selected tables, select "Drop" & confirm & they will be gone.
If u want to merely empty the tables of their content but leave them there, select "Empty" instead.