I changed the title of this topic, because it's not only a set of several cleanup scripts any more.
It's becoming something like a wide collection of plugins you can choose from... I've posted 6 plugins so far, here comes #7 and #8
The first one will help you with multiple selections. If you want to select all 43 copies of the same mesh you have created, select one of them and run the script
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It doesn't only work with meshes, it also works with spheres, cubes, cylinders, points, faces and edges. The attached image shows what the script can do in point-edit mode.
The second script is quite simple and it's a useful example if you want to learn ASL (and you may also find it useful as an Anim8or user...). It will select check all the selected points and select the nearest neighbours.