Rug doctor tips

[addler]

I'm attacking the carpets in my parents' home this weekend. They are dark green, now a middling green with dust. No idea how old they are as they were here when we moved in more than 20 years ago.

Any tips to get the best possible results?

Just use hot water, not the soap. A friend who's a professional rug cleaner gave me that tip years ago. Multiple passes with plain hot water.

Ooh I'm renting some this weekend so following for tips! I'm excited to see the dirty water that comes out 😁

No soap?! That sounds like madness! Has anyone tried it and can confirm the magic?