Positive-methods (as opposed to punishment-approach) trainers would not advise anyone to spray dogs, shake cans, or do other similar aversive approaches -- and I'd agree. You can easily introduce other problems that are even harder to manage (see below).
She is right around the age where dogs chew, and most likely, that should start to decline. However for some dogs, especially those who get the habit, this can be a permanent issue. She sounds like she has had the opportunity to get into this unwanted habit, so you have a somewhat greater challenge.
The single best approach is
management: eg: do not let her get access to skirting boards, furniture, etc. That may mean she needs to be blocked from accessing certain rooms: so close some doors in the house. It may mean that when she is inside, you use a large xpen to contain her, at least until the habit is broken and the behaviour less automatic. She also needs more hands on supervision -- maybe that means when inside someone clips her to a lead looped thru their belt so she cannot wander at will. Close the door so she is confined to the room with someone, not allowed to go off on her own and chew. If she is closely managed she can easily be distracted from chewing before she even starts -- which is where you want to break the habit. Rather than spray her, shake cans or shout, instead give her something else to do (has she done a good fun obedience class?) A dog that is asked to sit or go into a downstay... isn't chewing! A dog that can be sent to its favourite bed with a toy on command... isn't chewing!
Bitter apple spray on the boards and furniture itself helps in some cases, but in my experience, is ignored by many dogs.
The other approach to go along with the above is finding the toys that she is actually interested in to chew. Generally a kong with some interesting stuffing -- mashed banana and a bit of kibble for example (though subtract all such things from her daily food intake at meals) is generally a lot more successful than being given a rubber toy for most dogs. I have a whole household of dogs not remotely interested in chew toys excepting rawhides and Kongs.
Have a read of the three short articles here and I am sure you will get some helpful ideas too!
http://board.cavaliertalk.com/showthread.php?t=25333
Deterring unwanted behaviour is always a matter of putting in time to train for what you do want, and management to stop what you don't want. Both of these are far more successful than scaring or punishing a dog, who may only start to do the unwanted behaviour
secretly, when you are not there --
spraying/noise etc tends to teach a dog not to do something *when the owner is there*, not to stop the behaviour and find other things to do.
Also: be sure to praise her and toss her a few bits of kibble when she is doing what you do want -- chewing a chew toy, relaxing in her bed, laying quietly -- this gives a dog good behaviours to recall and repeat. Too many people instead of encouraging the wanted behaviours all the time, use 'no' more than any other word in their dog communication vocabulary (hands up as we all probably do this!). Often there are many different contexts for 'no' and the dog likely has no idea what 'no' means (imagine if you were doing a task at work and your boss just stood at your shoulder and kept shouting 'no' at you without explaining what she wanted you to do -- it is about 100 times more confusing for a dog!). Just like people dogs need to know what IS wanted rather than just being told don't do this, don't do that, don't move this way, keep your paws off that. And managing them thoughtfully so they don't end up doing what we don;t want in the first place (and so bad habits aren't formed -- these are MUCH harder to stop once they have started!) is 90% of good training.