For those asking how to apply thermal interface material (TIM), Heatsink compound, Cooler sauce, or whatever you like to call it, here's a tip. As scarlet said, spreading IS the best way to apply TIM. I used to work for an electric vehicle research company, and as you can imagine, our MOSFET's and VRM's were a "bit" bigger to say the least. After twenty years of experimenting i settled on a way to apply TIM which has never let me down, and always provides superior results if done right. It's easy, it's quick and only takes slightly more effort than just globbing it on. lol.
As Scarlet suggested using a credit card or similar is a good way to apply it, but NOT using the edge. Initially using the edge to get it on is fine, but then you need to move slightly inboard. I've got a picture i'll add to this post to show you what I mean. It's quite simple, you bend the card slightly by pushing down firmly on it as you spread the TIM. This helps expel any bubbles and applies a nice even thin layer of TIM. I've used this on electronics of all sorts including CPU's and GPU's of hundreds of systems. My current RIG has an i5 6600K that idles at 27'c and tops out at 38'c. My GTX 1070 FTW idles at 28'c and tops out at 64'c. Can't take credit for the FTW, that's out of the box and i've had no issues, but mine was built on 10/10/16 according to my info page. I've run it while monitoring temps with an infra red thermometer and the back of my card sits around 35-40'c. So it seems the pad fix is very effective. I also run a more aggressive fan profile, but not by much.
Anyway, as you can see by the picture you use the part of the card slightly away from the edge as the edge can scrape away the TIM as you're spreading it. This way you can expel bubbles and the edge is flat to stop it digging up TIM as you're applying it. It is slightly messier on surrounding areas but a couple of wipes can clean that up in seconds. Then you're good to mount your cooler and carry on. This works well for both GPU and CPU coolers as well as all kinds of electronics with large heatsink areas. it's fine to change direction if one area isn't covered well and keep going until it's completely covered and then do the aforementioned clean up. Hopefully this helps some of you worried about your cards and the most effective way to stop them self igniting. lol