how to delete from _Items table

[thebigbody]

i have a server that has been opened since years
and now my table _Items -which there are huge operations on it- is kinda full
so when any operation is executing the table will take little long time to do it
any solution to delete "lines" from it to prevent this completion ?

[B1Q]

update _Inventory set ItemID=0 where ItemID=ID64
update _ItemPool set ItemID=0 where ItemID=ID64
delete from _Items where ID64=ID64