I recently purchased the large cake of Colleen's CB, which is great btw.
I had 4 sample soaps left, and about half of one. The samples didn't work to well for me as I posted before. I took all of them, put them in a little glass bowl, that I use for shave soaps, (avialable at Wal-Mart) with lids mind you, Put it in the microwave at 50% power for about 20 seconds. They melted great into one regular size multi fragrance soap. No problems, no burning, no nothing...I mixed 5 extra drops of glycerin. It worked great.
Just FYI.....