Power down the system
Unplug the power supply
Remove the GPU from the motherboard
Disconnect all PCIe power cables
Use compressed air to remove loose dust
Wipe the exterior with a dry microfiber cloth
Dampen a microfiber cloth with 90% or higher isopropyl alcohol
Gently clean the heatsink, shroud, and backplate
Use cotton swabs with isopropyl alcohol for tight areas
Clean the fan blades carefully by hand
Avoid getting liquid on the PCB or connectors
Let the GPU dry completely
Reinstall the GPU
Reconnect all power cables
Power the system back on