Well I have witnessed to JW's and Mormons for many years,
on the front porch, the back porch or out on the front yard.
I have also knocked on THEIR doors with Gospel tracts, that's always interesting...

I just don't invite them in my house.

I was a Sunday School teacher for over 10 years, (college and career adults) and I only lost one young lady to a cult, it was the Mormons. It started as a social affair, she worked with several of them and she was invited to their events and eventually she started inviting them into her apartment. That's how it starts.

Now we talked with her, several of us visited her and tried to answer her questions about doctrine again and again. I sent some of the women to visit her as well.

It took a long time for them to sway her, about a year as I recall. Well one Sunday she came back and made it known around the church that she had become a Mormon and joined their program. Then she started coming over to my house, and wanting to talk to me about doctrine. Guess what? yep---I no longer allowed her in my house. Why? Was it because I was afraid of her doctrine? No, it was because of what scripture told me. I will leave the exegesis of that scripture to others. But my advice is the same, don't let these people in your home.