This article by does a very good job of capturing the spirit of courageous engagement and open-hearted listening that is key to being effective with racism skeptics. Suggestion number 2  - integrate your experiences - is particularly important.

https://medium.com/@kimberlydark/six-things-white-people-can-do-to-reach-friends-and-family-members-to-end-racism-48de9d3f24c0