Volunteering with your kids is fantastic! Also, let them help you as much as possible with donating to charitable organizations. Even young ones can help gather goods/clothes from the house and put it in bags and take it to a shelter or drop off point. Explain how this direct type of help really matters.
I also found that exploiting conscience matter issues or issues where my wife wasn't 100% on sure footing (dub wise) - like going to the YMCA, limited after school sports or county sponsored classes and activities, The dubs aren't against all of those things but they are against the time spent with non-witnesses - which is exactly what you need for your kids. Interaction with regular kids.