There are several different types of big screen TVs. There's CRT (cathode ray tube), and LCD (liquid crystal display) and plasma TVs. LCD and plasma TVs do not lend themselves to home cleaning and must be referred to a qualified technician. However, if you have a CRT big screen you may notice that over time your TV picture has become fuzzy and has lost much of its sharpness. You may notice the colours becoming dull and lifeless. You might make the mistake of assuming that your CRT TV is simply old and needs replacing. However, In many cases the fuzziness and lack of colour and detail are due to nothing more than an accumulation of dust on some of the interior components. Removing the back of your TV and gently wiping the dust off of the mirror and off of the three colour "guns" (red, blue and green) is generally all that is needed to make the picture on your CRT big screen TV look virtually as good as new.
Unplug the TV power cable and remove the cable, satellite or antenna lead. Wait 30 minutes before continuing to allow capacitors and other components time to lose some of their stored electrical charge.
Remove the screws holding the back of the TV in place using your Phillip's screwdriver. Carefully remove the back panel when all the screws have been removed. Do not twist or put torque on the back panel as you remove it.
Spray rubbing alcohol onto your microfiber cloth and carefully clean the mirror that is attached to the inside of the back panel that you just removed from the TV. Rub gently so you do not change the alignment of the mirror in any way. Make sure there are no smudges or streaks on the mirror when you are finished. Set it aside for the moment.
Locate the three colour "guns" inside the TV. These should have patches of colour on them: red, blue and green. Spray more rubbing alcohol onto your microfiber cloth and carefully and gently wipe the ends of the guns to remove any dust, cobwebs or debris. Be careful not to change the alignment of the guns.
Screw the back panel of the TV back into place, plug the TV in and attach the antenna, satellite or cable lead.
Some brands of big screen TVs allow you to remove the front protective glass from the TV. If your TV allows for this, clean the inside of the protective glass with your microfiber cloth sprayed with rubbing alcohol and gently wipe the front side of the picture tube itself with your microfiber cloth and rubbing alcohol.
Do not touch any electrical components inside your TV while cleaning, as certain components can hold an electrical charge even after the TV is unplugged.