Muting strings is one of those techniques which can make your strings sound a lot darker.
Most of you readers will be aware of this technique when it comes to muting your low E and A with the technique called “Palmmuting”. This technique is used in a lot of Rocksongs, usually it is applied when using distortion on the electric guitar.
Why not extend this technique to ALL your strings? Not a problem you may say, true but watch out:

Stratocaster players or anyone with a vintage style bridge and a Strat style electric, will find that they will need to adjust their handposition when it comes to muting the top E, B and G string. The volumecontrol also seems to be in the way, you will need to curve your pink around it to get comfortable.

Start by putting your palm accross the whole bridge, this will now be at a different angle compared to when you only mute the low E and A.  Try your usual technique and watch ( and listen! ) what happens when you try to mute your G, B and E when using the same technique. Changes are you will need to adjust your palm.

A similar story for acoustic guitarplayers, you will need to adjust the postion of your palm as well.

This technique may be easiest for guitarplayers with a Tune-o-Matic style bridge (Les Paul style of Guitars). The Volume and Tone controls on these guitars seem to be well spaced enough, position of your palm should not have to change too much from how you normally hold it during playing.

  What is the use of this Technique?

Muted melodies on your top strings which will stand out in the mix. These sounds are also good for percussive playing all across the fretboard.

Too many ideas to mention really, just try it, experiment and see how you can fit it into your style.

Have Fun.
Eddie