I've tried ALL of the liquid products, including an aerosol one. Fiber_lok
(rubber sap with some ammonia in it) was a huge disappointment: it came
off like dripping mucous when I washed it in the machine, and my rugs slid
even more because it dried slick. And the aerosol had no effect
I love the new brush-on product simply named Rug Anchor. It's a bit
expensive, but a little goes a LOT farther than the bottle claims, and it
stands up to HOT machine washing and the clothes dryer. My rugs and other
things I used it on a couple of years ago are joys now.
By the way, the product's available online only, and the company has
discounts on multiple bottles, so you can split an order and save $.
3M VHB double sided tape. It works very well, but it can mar the finish
on the floor depending on the type of floor.