@d2girls - I use Glad plastic wrap. Seriously, if you stretch it tightly and wrap multiple layers in all directions, it is better than the original plastic bags. It clings to itself, holds tightly and prevents any movement between the plastic and the casing of your electronics. I've used it for electronics and speakers. Check my feedback and you'll see several comments about the quality of my packing jobs. Many of those were using Glad plastic wrap purchased at the grocery store.
Missing the plastic bag for shipping for my amp...
Well as anyone who knows Pass gear is aware, the amps and preamps usually come with a thick plastic bag. I know this is probably a stupid question but here goes: what can I use as substitute if I lost the original bag?