Depends on which fans you have. For my Sapphire HD 7950 for example you can pull off the fan. Peeling the sticker won't help. Fortunately there is the option, as almost every single card had developed horrible rattling over time at least once, most probably due to the low quality lubricant Sapphire uses for their fans. I usually take them to my lab and pipet 2 µl of mineral oil into the hole (although there are certainly better and more suitable oils/greases for this).

Here's a small guide:

https://litecointalk.org/index.php?topic=17726.0