Rusty's Grenades Fix

If your willing to learn then here is the simplest (and bug free) solution:

1.Open Rusty in the GECK
2.Find Rusty under NPCs (my prefix is always "I5K" without quotes) in the object window, open him
3.Go the inventory tab and remove his custom grenades
4.Close and save.

These items aren't embedded into any scripts or quests, and as an unplayable item they will not interfere with your game in any way.