Do you think sand- or other media- blasting would be a possible way of getting dynamat off?
Just outta curiosity, why? If I had the means, I'd love to "dynamat" my ride! :snacker:
yeah, what on your 4runner has Dynamat on it??
Heat it with a hair dryer or heat gun (carefully) and pull it off. Get a corner started with a putty knife, grab the foil layer and the tar layer and slowly pull it off the body so it has time to stretch and release. It's a huge pain in the ass.
By the way, if you try to blast it you will just end up with a layer of tar with a nice "sand and perforated foil inlay" and it will make proper removal all the more difficult.
The rust is going to add some excitement to the job and if you find it's not coming up very well around the rust it may be better to use a utility knife and cut around it. Or just pull up what you can from the rust and deal with the cleanup of that spot later.
There is also the possibility that the rusted area may have created a "bubble" where all the adhesive is no longer stuck to the body and instead the underside is coated with dust. If you find a bubble like that, I would cut around it with a utility knife and pull up that section. This would certainly make the job waaaaaay easier, and if you find it that way I would buy a Powerball ticket soon.
Good luck!