Has anyone tried these SnugPlugs?

I think the concept is prolonging use of an already ruined outlet

Go for a better outlet.  I noticed a bigger improvement in sound over new a/c power cords.

For $10, I'll just buy a good outlet. 

Put "audio" outlets on my 2ch and HT setups, even changed my bedroom one. The new outlets hold cords very, very well! It's hard to plug in, and even harder to unplug. Did not go crazy on outlets, they were around $30 each. 

Sadly, most house outlets are dirt cheap bulk items, you know the 20 pack for $10 kind of outlets. They do not last, and are crap to begin with. If you replace them with good outlets that cost $2-5 each, they will be a huge upgrade. 

On my house, they backstabbed most outlets. Just changing that was an upgrade. 

Furutech GTX-D Rhodium outlet or Cardas 4181US Duplex Power Outlet are way to go. Lot's of these fora too.

I replaced my AC outlets with medical grade outlets and they hold great. I would like to find something to snug up my IEC connections. I have 2-3 that are jiggley and I’d definitely like to tighten them up.