In the summer, it is dangerous to leave even a small vent open, let alone a window – you won’t have to wait long for uninvited guests in the form of flies.
Fortunately, getting rid of annoying insects is not that difficult – you don’t even need commercial chemicals for this.
To do this, you will have to make a trap, once the flies get into it, they will not be able to get out.
Take a small glass jar – half a liter or one liter.
Pour 300 ml of vinegar here and add a small amount of liquid soap. Mix all the ingredients well to get foam.
You are already at the finish line - all that remains is to cover the neck of the container with cling film. If you don't have any, a regular plastic bag will do.
Securely fasten the improvised "lid" and make several holes in it large enough for a fly to crawl through.
The trap is ready - place the resulting structure on the window. Not a single curious fly will be able to fly past, and once inside, it will never be able to get out.