I often see eggs used in spells, with good reason, of course. Eggs signify new birth, regrowth, or transformation, in some cases. They are also commonly seen as a very 'pure' ingredient to work with. However, there are always some warnings and we must be very careful with using these.
1. Avoid using raw eggs in spells.
This should be obvious, however it is not. Whenever I see raw eggs, egg yolks, or egg whites used in spells, more specifically in concoctions that must be consumed, I become very worried. Consuming raw eggs is an very easy way to give yourself many diseases, including fatal ones, such as salmonella.
2. If you are using an egg and it is cooked, do not leave the yolk moist.
Unless you know for sure how to cook sunny-side up eggs, many times the yolk of the egg will not be cooked, and in some cases could do the following; either mess up the spell (Although, subconcious worry) or it could once again cause disease.
3. Broken eggs in readings / when using
Some say that if you go to pull an egg to use in a spell and it is broken, that the spell has failed and will backfire. Of course, this is mainly superstition, however broken eggs can be rotten on the inside, causing not only awful smell, but also an awful mess to clean up.
4. When you're done, make sure you clean up the area. Eggs are messy, some consider them like raw meat; you would not leave a steak on marble then put it away, only to not wash the marble after.
These are just some things to watch for when using eggs in spells or reading over spells that contain eggs. Of course, more people can add more reasons as well as counter arguments to these; I am always happy for debates.