Wal Mart has a product available ( and I don't know if all the store's
have it in stock)
"Tint Off "
"Tint Away"
"Tint Gone"
Or something close to this description in the automotive dept.

The one problem here is; while it's busy removing the tint and glue it's
also softening up the adhesive for the wire's for the rear defogger .

You have to be real careful not to damage the 12 volt defogger grid or
you'll lose it.

Your almost better off replacing the rear hatch glass than go to all the
hassle of taking the tint out.