how to delete custom verbs?

I've used the talk to; talk; speak to; speak and then added an extra option of my own before realising i could have just made a new one(talk to; talk; speak to; speak; ask #object# for a story), and now when ever i try talking to any character it says talk to; talk; speak to; speak; ask #object# for a story even tho i gave them the normal built in verb for talking to.