Hi, I recently got a free pair of Boston Acoustic bookshelf speakers from a friend, and I'm using them for my center channel. I've since learned (by the weird color patterns they impose on my TV) that they are not magnetically shielded. Thankfully, my TV de-gausses itself when it's powered on! Is there any non-destructive way to shield them? I'm not sure if he's going to want them back in the future, so I'd prefer not to crack them open. Ideas? Thanks, -Brett.