Do you have a favorite carpet soap or recipe for one?

I'm going to clean my carpets with a rented carpet scrubbing machine.  A friend who used to be an apartment house manager cleaned the carpets when apartments became vacant.  He said that a soap sold by a farm supply store was far better than that sold by the machine manufacturers.  Unfortunately, it's not available now.  He recommends that I ask around for suggestions.

So—what do you think I should use?

I know very little about carpets, but we have 5 handmade wool area carpets from India and was told that they take a special cleaning technique and soap. Fabric may be critical to your selection.

Do you have a favorite carpet soap or recipe for one?

I'm going to clean my carpets with a rented carpet scrubbing machine.  A friend who used to be an apartment house manager cleaned the carpets when apartments became vacant.  He said that a soap sold by a farm supply store was far better than that sold by the machine manufacturers.  Unfortunately, it's not available now.  He recommends that I ask around for suggestions.

So—what do you think I should use?

What brand did he recommend?

Has always just been Rug Dr brand!