Thanks for your responses. I expected that it should be ready solution... Thanks to you I know the magic word: "sill expander". Will go to HD to find out why they did not mentioned this. To HomeSealed Exteriors: this sill will be replace, it is a better part :-( Out of five windows one sill is a mess (this one) one is OK and there in perfect conditions,...

Here is what I would likely try (assuming I understand correctly -- that there are only a few that are this bad; that under all that built up paint and mildew there is metal, not wood; and that you want to have the finished pain surface look even and neat and stay looking nice. I would not worry about tape/adhesive marks and would put away the WD40. I would make the time and space to have everyone out of my way and to have a good exhaust ventilation and tarps/drop clothes and shop vac set up along with proper eye, ear, possibly respirator (definitely some airway protection and disposable as well as heavy duty neoprene gloves. i would spend the time and effort to remove all of the built up crud -- so removing tape marks is a non issue. If I understand your gunk problem, you'll be removing the years of old paint and sludge underlying the tape adhesive marks. I'd first try to chip, chisel, dremel, grind and sand off anything that I could without damaging the steel underneath. Vacuum that all up, wire brush and try to remove more. Vacuum again. Then, following the manufacturer's direction and with proper ventilation and tools and protection as discussed above, I would begin applying the "best" (most effective, lowest VOH paint stripper remover I could get. What you use would depend upon a few factors and the types of paints in that cracked sludgy stack. You'll want to protect yourself floors and adjacent areas. You can use layer of rosen paper atop a tarp and and the paper gets messy, swap out. Have some chip brushes, steel scrapers and gougy tools and some disposable paint pail liners to toss the scraped off partially disolved old paint into. (Dispos of properly as it will be flammable. Just keep working on dissolving the old paint, scraping it free, repeat...until you get almost all if not all of it off. It's work and messy. Then, after what you cannot get off has dried and 'cured' a bit, you can try to sand and scrape the rest free. You may be able to do some of this outdoors. You may want to hire someone to do this part for you. I have removed old alkyd paint this way, then, in the case of a large, pick wick bead board back bookcase, washed it with TSP (Tri-sodium phosphate --- there may be restrictions on its use or availability from state to state). Let that remain a while, then rinse off with clear water. Allow to dry thoroughly. If only working indoors, you can use terry rags, pails and poly plastic drop clothes with "towel / rag dams" to protect your flooring. Allow the project to dry well. Shop AC dry, towel dry, dry nooks with hair dryer. You don't want to create rust and you will want to treat / remove any existing rust. I would do all of this way before even considering priming and painting or addressing the opportunity for condensation. A faster and less messy way to address all the gunk might be to pay someone with a sand abrasion set up. It may be costly. Perhaps you can barter. Ask around at some auto body shops or vocational schools. Best of luck. It will look so much better when you get it cleaned up. One trick to help with condensation is to consider a dehumidifier or a small fan. Always went cooking kettles and dishwashers with a kitchen exhaust fan. Always run your bath and shower exhaust fans for 15 or 20 minutes after shower use. In the winter or fall, we sometimes crack a window and let some of the very dry winter air (New England) come in and exchange with moist air. If in the fall or early winter and you have a lot of moisture in your house from a humid fall or late summer, be careful about keeping your rooms too cool until a lot of that moisture wicks out of porous walls and floors. We've got a tight house, so have to mind the level of condensation growing on cold Windows (we don't have the best windows). If you have a house full of large dogs, you're apt to get a lot of condensation.

The problem with doing touch ups or partially doing an area, is that it tends to make everything else dingy. From the standpoint of labor, it is also disproportionately labor intensive. You still have to protect the whole room, even if you decide not to do the ceilings, for example. Similarly, it is far easier and time efficient to do the woodwork before the walls, whether spraying or brushing the woodwork. Were I trying to save money, I would opt to do one or two rooms completely, rather than to do the whole house incompletely.

I finally dug into this project. As a primer, these windows (as well as the siding in this part of the house) were not properly flashed, which also resulted in rotting portions of the osb next to/underneath the windows. so what was a ”I’ll fabricate new frame portions and replace those” became ”I have to pull of a lot of the siding off around the windows as well, replace/repair the osb (I used plywood), and put on proper housewrap and gap between the siding wood and the wrap” This house was constructed right before the mass availability of superior housewrap, and the siding ”logs” were nailed directly to the tar paper wrap with no gap . Definately a learning process for me about proper construction. So to summarize, there were several sins of construction done on the walls and windows, which resulted in this problem and increased the time of this project, After addressing and repairing the rotted area of the walls and putting on housewrap and vertical furring strips to allow drainage/ breathing betweeen the siding and the wrapped wall, I removed the rotted fronts of the frames (the middle sections), stabilised the remaining good wood, constructed new frame peices, used flashing tape to seal the stabilized remaining wood, and added the frame sections in. On the worse side that i repared sections of the wall, i also added flashing to the top and bottom of the window, and made sure to have weep holes and paths for water to run outside. The side of the house that wasnt as bad (pictured above) I will address the wall/siding next year. the Frame area was the most critical, so at least i got that done before the weather gets bad here. I do plan on redoing this whole side sometime in the future, but this should give me a few years to plan that out (and save up) . I’ll add an after pic, later today if i can get home before it’s dark .