OK here's the situation. I've moved in to a flat, and just outside the flat is some kind of contraption that makes a lot of noise. I think it may be a generator for air conditioning. There's a shop downstairs, and I think it's theirs. I can't make any alterations to the flat in any way, because I'm just renting, and I'll be gone in about 5 months time, so I want a quick and easy "solution".
The existing double glazing looks cheap and nasty. My "bodge job" approach to this problem was to buy 3 sheets of thick lamenated glass, and simply wedge them inside the inner window area, so that they sit on top of the window sill, a little bit like secondary glazing. Luckily, there's a kind of perimeter ridge area within this inner window area, where I can lean the sheets of glass against. But because the glass sheets are fractionally too tall, there's not enough room for me to wedge them between the window sill at the bottom, and the top part of the inner window area.
If I can't economically get 1mm shaved off the sheets, I could try a different approach. But plan B is even more mad than the above plan A. I could get a wood plane, and shave off about 1mm of the front window sill area! That would allow me to get the 3 sheets of glass wedged in and propped up inside the inner window area. However, this will cause one significant problem: after planing the front part of the window sill wood (the area which is furthest away from the existing double glazing), the entire window sill wood area will get 2 height levels. One level will be lower (at the front where I want to prop up the glass), and one level will be 1mm higher (at the back, near where the existing glazing is.) So, you'll see a "ridge" where these 2 levels meet. Could I sand that ridge down, to kind of merge the 2 levels, so it won't be noticeable? Of course, I'll need to repaint the window sill where I have used the wood plane. The flat is a bit of a dump, and I doubt whether the owner cares about this... I suppose the worst that could happen is I'll either get a deduction on my flat rental deposit, or I'll get sectioned for being a loon.