I agree with boiling water and dish water liquid and a good scrub. When that doesn’t work I would use the sunlight block soap, apply with hot water and scrub and repeat

Rugs also cover a lot of awkward spots if you have stubborn stains

Boiling water + dishwashing liquid!

I bought a Bissell spot cleaner it’s amazing similar to a handy vac i paid it off with mylayby

If your carpet is white you can use anything. Truthfully once you’ve found a few upholstery, carpet or stain removal products you like, your best friends will be repeated application and a quick response time.

Professional carpet cleaners or try hiring a machine. I bought a steam cleaner for this issue, it’s taken a few repeats, but has removed or lightened most stains

If, like me, you prefer to use Natural cleaners try rubbing light carpet stains with a mixture of 2 tablespoons salt dissolved in 1/2 cup white vinegar. Let the solution dry, then vacuum.
For larger or darker stains, add 2 tablespoons borax to the mixture and use in the same way. Good luck!

Try “Carpet Power”. You can buy it at the supermarket. I used it on one upholstered chair and it did wonders!