[SamAdams76]

To ensure that the shell is easily removed, just before boiling, shake each raw egg until you feel the liquid inside start to move around. Thus, you have already separated the shell from the membrane.

It also keeps you from re-boiling an already boiled egg, for if you never feel the liquid moving around, it's either already boiled or there is something seriously wrong with the egg.

[SAJ]

Simply spin the egg, narrow end down, on the counter. If it spins upright, it’s already boiled. If not, it’s not.

[Banjoguy]

Also, spinning an egg will reveal a liquid core by the egg refusing to spin.

However, this week I will try your method of separating the membrane.

Thanks!