DO NOT use alcohol on older 78's. You will ruin them.
The RCM generally isn't the issue. It's the cleaning fluid used and the failure to adequately remove the fluid and contaminants from the record surface.
A few sources that should be reviewed and contemplated:
https://forum.audiogon.com/discussions/a-very-long-primer-on-record-cleaning-fluids
The above is VERY long - but worth the time to read.
This one is from wikipedia:
https://en.wikipedia.org/wiki/Conservation_and_restoration_of_vinyl_discs
Library of Congress:
http://www.loc.gov/preservation/care/record.html
People wanna always take shortcuts. Methinks Mr. Tang's method of applying WD40 is just another shortcut along the lines of using wood glue.
At the very least, get yourself a Spin Clean if you can't afford a RCM
ultrasonic or otherwise. I personally use a Okki Nokki along with Audio Intelligent Vinyl Solutions products and I'm very happy with it and the results I obtain.
Bottomline: It's your choice. It's your record collection. It's your money.