I tried that hard for quite some time but never managed to get a purely on-topic timeline. Follow 10 experts who post mostly about topic X and you'll constantly find at least one of them posting something different at any point.

For example you can't subscribe to grugq for political-infosec content without some IRA memes. And I don't mean that other people shouldn't post stuff they want, just that I'd like to see a filtered view of their posts most of the time. After a few iterations I gave up Twitter almost completely.