This project could not be any easier. You can buy the base soap in any craft store, or online, an a wide variety, such as olive oil, glycerine, shea butter, suspension and non, etc.! I used ArtMinds Shea Butter soap, suspension formula. What "suspension formula" means is that whatever I add into my soup will be "suspended" throughout the finished bar. With some formulas, coarse ingredients can sink to the bottom of the mold during cooling, which could be a desired effect or not.
Cut the soap into chunks and place in your microwave-safe bowl. Melt in microwave (or follow the stovetop directions) according to the directions on the packaging. Due to the size of my bowl, I was only able to melt half of the block at a time.
Tear open the tea bags (3 per lb of soap) and pour contents into the melted soap. Add a dash of vanilla and mix thoroughly.
I tempted fate here and stuck the mixture back in the microwave again for 30 seconds to try to let the heat infuse some of the chai scent into the soap. Worth the risk.
Once your melted soap is thoroughly mixed and infused and such, pour into soap mold and stick the whole mold into the freezer for 30 minutes. Usually, you would just leave the mold out to cool on it's own, but as I only had the one 4-bar mold, I got impatient.
Once cool, pop the bars out of the mold(putting them in the freezer helps here) and set them flat on the cooling rack. Allow the bars to rest on the cooling rack for 24 hours. This allows them to "cure". Most things you read online will tell you that melt and pour soap doesn't need to cure, but I found that the quality of my soap; lather, scent, texture; improved after letting it sit out overnight. If you notice a lot of moisture or oil on the surface of the bars when you first pop them out, don't stress, they will be absorbed back into the bar while curing.