For some reason I started thinking about what the "classic enemas" were. I guess these could be split into "true classics" used before 1940-1950 and "modern classics" since then, but the criteria would be that they are safe, effective, not too hard to make, and safe.
Here's a list of the "true classics" I can think of:
pure water/tap water. The most "classic" ever, been around since antiquity.
Soapsuds. Don't know how old this is, but it's up there. Works well, easy to make, and pretty much all-but-synonymous with "enema"
Glycerin and water. Very effective and time proven
1-2-3 (1 part Epsom salts, 2 parts glycerin, 3 parts water, all by volume). Probably the first "mini-super enema," mentioned in a 1920 article as if it had been around for a while already.
I don't know how long normal saline has been used, but I guess that probably is on the list as well.
Any others on the True Classics list?