Great blocks. I got some 1930's Sun Bonnet Sue blocks from a friend - yes, original to the 30's! I soaked them in cold water and OxyClean. I would soak for overnight, empty the water and gently press out the excess water (no wringing) and then soaked again. It took about 4 soakings but they came out really nicely. They are on my to do list for this summer.
Good luck with your beauties!