Delete PPP ghost interface

Hi, i need a help..
i used router rb411UAHR, ROS version 6.4 and rb411UAHR ROS version 5.24.
i got issues with ppp-out(indexes) ghost interface. so far i did delete this by manually when ppp-out(index) created. i need a script to delete this things when my router create this indexes ppp-out.
like picture below, there is a time i got this ppp-out(indexes) from 1 until 32..
https://s31.postimg.org/48p938oez/PPP_Ghost_interface.png

please, i’m waiting forward hearing from you guys..

Regards.