Mi-24 Hind

Some PE added. 

Cut off plastic behind all grilles. 

Mi got pneumatics! 

I believe I found the algorithm!
0. Prepare the detail so that it is all on one side of the model. This way the solvent won't leak out. It may make sense to divide the part into several parts.
1. I transfer the detail to the plastic on water, place it in the right place and fix it with a tight cotton swab. The cotton will soak up all the water from and under the detail.
2. With a brush, I apply a little solvent so that the lacquer backing begins to melt and weld to the plastic. Wait until it all evaporates. It is very important not to rush, otherwise you can move the detail, or worse, part of the detail.
3. I apply the solvent again, but a little more. If the part sat well in the previous step, you can begin to gently wash away the dissolving lacquer with the same brush. At a certain angle, you can see how the solvent becomes thicker. This is the dissolving varnish.
4. I dab the brush on a paper towel, wash it in solvent and try to wash away the thick dissolving varnish with a drop of fresh solvent.You need to repeat this step, blotting the brush until the solvent is no longer thick from the varnish. The solvent should not collect in big drops! They should be blotted with the brush.
5. I dry the spot with air from the airbrush and check that there is no excess left. Steps 3-4 can be repeated even after a few days.