You can definitely train a cat to stay off of furniture and drapes, but you have to be completely consistent with it - like training any animal to do anything, really. Try a spray bottle and give it a little spritz along with a firm "no" and take them off of the offending furniture and NEVER use the spray bottle for anything else (keeping them off counters, etc.) - the key is total consistency so they learn exactly what they're being told not to do. There are also little covers that you can buy to cover their claws, but I personally think they're not necessary and sort of weird.
And just my two cents - I think declawing is totally horrible. Absolutely no judgement on you, jenfen, 'cause I know it was acceptable at one time in the US and there's not been a lot of negative publicity about it, though that's starting to change. I volunteered for a long time at the SPCA and the policy was to not allow adoptions to anyone who was considering it. Basically a cat's claw is the equivilent of the first digit of our fingers - so imagine having your fingers cut off to the knuckle - it would really limit how you could use your hands and it does the same to a cat. It takes away their ability to climb, to defend themselves, etc. and even if they're strictly indoors, you can NEVER absolutely guarantee that they won't one day escape or that some day they won't end up living with someone who let's them outside. And sure, they get used to it, but I believe it's cruel. Again - no judgements intended - purely my two cents on a subject I feel quite strongly about....