My genuine suede boots got an unknown oily spot on the right shaft (I'm guessing from food). I used Nikwax Footwear cleaner generously and I followed the instruction to wet the whole boots. After it dried, I still saw the spot. I was disappointed. A year later, I decided to try again and this time I did it!

WHAT I DID DIFFERENTLY: after cleaning the boot as instructed, I still saw the spot as I did last year BUT this time I took a soft old toothbrush and brushed the spot vigorously after the boot is dried. The fluffing job did very well! The spot almost disappear entirely. You wouldn't even see it unless you are me and know it was there. Make sure you fluff the entire boot (and the other half too) so you won't see the difference. I almost got rid of these boots and now I'm keeping them. If your boots are heavily stained you may want to wash it a second or third time. In total I washed mine twice if you count last year's attempt.

The waterproofing spray also worked well for my other pair of suede boots. Water beads on them and not penetrating. I almost used the entire can for a pair of full suede boots about mid calf height. The suede still feels really soft to the touch afterwards. Just like promised :)