Hi Dave,
In my opinion, this question is a little bit "touchy" and that is mostly because there are so many juices on the market today--and if you are buying a prepared juice you have to be careful about what the additives are. Here is more or less a rule of thumb to follow: some natural juices are okay if they do not have harmful preservatives and/or added vitamin C or ascorbic acid, as this will cancel out the effectiveness of MMS. Never choose a juice with ascorbic acid! Fresh juice is best. We have found apple, grape, and cranberry juice to work well with MMS, but again, it should be natural, without preservatives and not have added vitamin C (or ascorbic acid). Never use orange or tangerine juice in any form with MMS.
I have found that if you want to be sure, the best thing to do is test the juice with a LaMotte test strip. Whatever juice you want to use, pour 4 ounces of the juice into a glass, and add a 3 drop dose of MMS1 to it. Test with the LaMotte strip and see if it comes out to somewhere between 25 to 50 on the strip. (It should be between 25 and 30 if your MMS is the right dose. ) If this is the case, that is good, your juice did not immediately cancel out the MMS, if that was the case your strip would be very pale in color. Then cover that juice with the MMS drops in it and leave it sit for 1 hour. Aftter the hour, test with the strip again. it should read the same, or nearly the same. It might go down in strength a little bit, that is ok, but if it's nearly the same, then you know your juice or herbal tea or whatever you are testing is okay. Again, if you do this test and the first time you put the strip in it is not even close to 25 on the strip, then you know for sure your drink is not compatible with MMS.
I have found personally overall apple juice is a pretty good mix with MMS, I have tested many kinds of apple juices in various countries and it works pretty good--but be sure there is no ascorbic acid or added Vit C of any kind or other weird additives. Another tip, if you are looking to just mask the taste of MMS a bit, a squeeze of lemon can do wonders. Hope this helps.