Almost all (99.99%) tango sheet music available for free on the web is of such poor visual quality it is barely readable. It must be entered into music notation software to clean it up and prepare a working copy. This is time consuming.
I usually make the sheet music I’ve touched up available for download in pdf files. The notes aren’t changed. I may have entered the chords and identified the sections and/or phrases. And sometimes the lyrics are not included.
I have only one request: if you use or re-post any of the scores, please acknowledge this site.