91% isopropyl and Bounty paper towels work fine for cleaning the copper
after sanding it. Don't use cheap tissue that sheds. Also for double
sided boards I drill the registration pin holes before sanding so the
sanding removes burrs.
Here is an example of a double sided board done with this method, note
the 'copper' silk screen values etc.
https://hackaday.io/project/25741/gallery#86a5661397dafe0b3c4ffcc3110e0288