Hello tangomonkey, and welcome to Mrs. Clean's Forum!
We have cleaning tips on our site, but I wanted to search for the specific stain you had. Here's what I found:
There are a few products that others have had great success with on the same stain.--The first recommendation would be De-Solv-It. I read numerous testimonies that this is the end all to stain removal on carpets, clothing, furniture, walls and doors! There were even several specific success stories with pollen stains. I would try this one first. When I did a search, it stated that you could find it at Walmart, Kmart and other stores.
I have had great luck with a non-soap product called "Procyon". It has worked on grease, coffee (that set in carpet for over a year) and other stains. Blue Magic - was listed for carpet stains and this works on grease as well.
Try these suggestions, and hopefully the first will work! Let me know what you think. If you have any other stains and want to try household products as cleaners, you can check out
removing carpet stains.Good Luck,
Mrs. Clean