I would never de-claw a cat, it's barbaric and it will cause them to suffer even more if they ever got loose and couldn't defend themselves. They would likely starve to death.
They make rubber tips you can have put on their claws so they can't scratch your stuff up, but I don't know how long they last. It's certainly less cruel than cutting their fingers off, which is essentially what de-clawing is, but I don't know if it solves the problem of them getting loose and not being able to fend for themselves.
I think there are also some certain scents you can use such as peppermint, that will deter them from scratching various things.
