Disassembly, completely if needed instead of just a basic field strip. There are plenty of internet videos to help if you are unsure how to.

If you do a search you will find several threads/references to using 0000 steel wool with oil and light pressure to remove rust from areas other than the bore.

Given enough time, Kroil seems to loosen up most of the crud in old barrels. I wet the bore, let sit for a day or two, wet it again and go on like that for a week or two, then I start brushing. In bad cases it can take a few treatments to get it clean. I have also tried to plug the bore and fill it, but Kroil is so darn thin that is seems to find its way out anyway.

I might have already told you this in other threads, but I had an SVT-40 with a real rough bore a while ago. I had brushed it numerous time with bore cleaner (wearing out several brushes in the process) but it didn't get much better, so I figured it was a goner. I sprayed it with Kroil for protection, and put it away for a few weeks, then I sold it to a friend as a barrel change project. A few days later he send a video clip showing him shooting the "rusted out" rifle, and when I asked him how he cleaned the bore he said "the crud brushed right out and it shoots just fine now" :banghead:

Would you say Kroil would be safe on the outside blueing? I need to get rust out from the hard to reach places in the internals

I used Kroil once to loosen-up a beautiful Borchardt that had been stored for years and was "frozen-up" to the point it couldn't be dismantled. I simply removed the grips and then submerged the entire pistol in a container of Kroil for three days. After the extended soaking I was able to completely dismantle the pistol for cleaning. The only thing effected by the soaking was the crud and what little rust there was. The bluing was not in any way effected.

An old trick I have used for years is use oven cleaner on a warm barrel let it set for awhile. And use a cleaning rod with stiff brush attached to a drill motor and have fun going at high R PM's. Amazing results.