I am still looking for the answer to my question. Anyone care to give it a try?

I want to remove the electrical smoke detector. How do I do that safely?

1 Turn off main power
2...
3...

There's an answer @ Yahoo answers hope that helps

How to replace electric smoke detectors with battery ones? - Yahoo! Answers

While it's for replacement hope it works for removel too!

Can we ask why you are doing this? Are you removing or replacing?

You need to be careful with this if you're eliminating a detector. You don't want to do something that is not only a violation of the code, but a safety hazard too. Many homes have the smoke detectors on a dedicated circuit and should be marked accordingly on your panel box. But I know of a lot of electricians who like to put an often used light on that circuit if local jurisdiction allows. That way you know right away if you've tripped a breaker on your smoke circuit. Also, many detectors are wired in such a way that if one goes off, they all go off. As you can see, it's not necessarily a simple R & R job. You don't want to do anything that disables or compromises the function of the rest of the detectors.

While both Cobraguy and the Yahoo answer question removing it, neither mentions if you go ahead, the box must remain accessible.

If you remove it and ever sell the house, it would be possible for the new owner to hire an electrician to correct all the code violations and send the bill to you. Best do what you need too now to comply with current codes.

Here's 2 answers, I sent to your other post. Good Luck
Should be able to turn counterclockwise, some colckwise. Pull down, unplug 3 conductor from back of detector, If Part of an Alarm or Fire System, it may have 2 or 4 wires, Removing should not be done and may dial, or sound trouble. New battery and installation will be reverse of removal.
Some may need small tool to release if lock option enabled. It is only plastic, light pressure.

You can remove power, remove detector, and disconnect 2 or 3 wires from detector, cap off, turn power back on. Usually smoke detectors are installed, not removed, Don't leave yourself or family unprotected. Take Care