My lab is relatively new to CLARITY work. About 6 months ago, we were able to get a solid batch of embedding to work, to the point that we were successfully embedding tissue and passively clearing them. We followed the CLARITY wiki's embedding and clearing directions to the T. The first time, we made all of our own hydrogel solutions and found this success. Then about 3 months ago we were no longer able to get the polymerization to occur. The initial batch just stopped working. Since then, we have tried remaking solutions, improving degassing, buying standard stocks, monitoring pH, using replacements (APS instead of thermal initiator, fresh BIS, fresh Acrylamide) to try and nail down what exactly was causing the polymerization to fail, only to be left scratching our heads and unable to replicate. Turning to you guys, do you have any recommendations? Has anyone encountered similar conditions? Any guesses at all will probably help us solve this puzzle. Thank you.