The following is the most unused (but best) method of chometz prevention:
I was saying Likutei Tefilos and came across the passage below. This is a good way to accomplish the first thing written in Segulas For Pesach, and it is perhaps the biggest segula to keep us away from chometz. After all the cleaning, preparations and chumros one may have to keep themselves from chometz on Pesash I realized that the on thing that most people don’t do is ask Hashem to protect them from chometz. We can only do so much and we need to ask Hashem for His help. When was the last time you heard someone do this? That’s the beauty of Likutei Tefilos, there are tefilos for every occasion, and if there isn’t one that you can find, Reb Nachman taught to open your mouth and daven in your own words for any and everything you need – nothing is too big or small to ask Hashem for. The tefila below can be found here on page 26. Other tefilos for Pesach are from page 25 and on.
“And help us, save us and protect us, with Your abundant compassion, from the slightest trace of chometz or leaven, so that we should not find, in our boundaries or in our domains, the slightest of the slightest amount of leaven or chometz, all the days of Pesach. For it is revealed and known before You, Master of the entire world, that it isn’t possible for flesh and blood themselves to be watchful from the slightest trace of chometz, if not through Your salvation and compassion.”
(Likutei Tefilos 2:37)