We live in an older log cabin. Throughout the years was not maintained until we got it. Our windows are solid double panes. Throughout the years there must have been leaks in the seals, since we have little corpses of bugs on the inside of the window.. Besides the point, we are looking to replace our windows with vinyl. We have to take out the old ones, but is there any tips that we should look at doing with prepping the opening of the window prior to putting it in? Any help would be helpful. Thank you!