5 Things To Look For When Buying An Esrog
1. The Top Section is Crucial – Always start checking from the top, the side of the pitom or where the pitom would be. A black dot on the top that is easily noticeable renders the esrog pasul. A white dot would also invalidate the esrog, but most light colored dots are beige, not white. This is the most common problem to look for.
2. The Whole Body – Next, the entire esrog should be examined for holes or scratches that would make the esrog chaser, lacking. Also, numerous discolorations that can be seen from all sides while examining the esrog render it menumar, spotted, and pasul even if they are all only on the bottom of the esrog. Furthermore, brown spots may indicate a recent bruise which is likely to darken and turn black over the course of the next few days.
3. The Stem – The stem should be checked to make sure it is firmly attached and not likely to fall off.
4. The Pitom – The pitom should also be inspected to insure that it is free of blemishes and that it is strong enough to last the week of Sukkos. If the esrog does not have a pitom, the place where the pitom would usually be should be checked to verify that it did not break off, but rather grew without a pitom.
5. Overall Beauty – Of course it adds to the beauty of the esrog if it is a good size and has an attractive shape and color, but these are of secondary concern.
copied from Revach.net