Professional Carpet and Upholstery Cleaning

Try a microfiber cloth with water first, it may surprise you.
And for type, look for the coarser heavier pile ones that look like carpet themselves.

Thanks truthskr - any links so I can get an even better idea?

Its hard to find the thick pile one. Here's a pack at BBB where I would use the the thickest of the batch. With lots of elbow grease, microfiber pads get just about anything out.

http://www.bedbathandbeyond.com/Product.asp?SKU=11713416

It's hard because the product has been shaved down and converted for optimum marketing (meaning not to last too long).
See, this product's been in europe at least 20 years, here roughly 10 years. Back then it was real plush and thick.
It didn't gain traction here until someone actually spent the 50mil plus on advertising to explain to the consumer how it works. I believe it was 3m who bucked up and pioneered the advertising for it here.