One question I would pose to you is was the yellow part mushy or wrinkly. Where did you have the plant when it was turning yellow (sun, shade, half and half?) Were you fertilizing it? I personally believe that pruning off pieces of your plant to save them with out researching to see if they need to be saved is rather hasty.

Horsetail...I notice you're in zone 5..You said your Epi was in the ground,right?..Did you keep it outdoors during winter? In zone 5?
Yellow leaves can indicate overwatering..I would have done the same, remove..it won't revert back to green..
There are other reasons leaves yellow, but in most cases, overwatering is the reason..Toni

Toni is right when you have yellow leaves its from over watering, at this time of the year they should be resting and watering cut back, then start watering and light feeding in march, I'v done the same thing over the years and learn some times less is better when it comes to epies. at this point is cut the yellow off let the green cutting dry out for a few days and replant hold back on the water until you see new growth you can mist the potted cutting every other day or so
good luck with your cutting

Bear

Thanks for all your help. I kept my epis in the basement and had brought them up to start the growth for the spring. So they had gone from filtered light, temp about 60 and watering maybe everyother week to direct southern light, temp from 65 to 75 and watered at least once a week.I can see that I deffinatly over watered but how about the rest? Did I change them too rapidly? I just did this about the 21 st of March.