The so-called liquid metal thermal compounds are well regarded for their heat conductivity, but they come with extra hazards. They are thus not the best choice for novice or nervous PC DIYers. This fact is illustrated very clearly by a graphics card sent to overclocker Roman “der8auer” Hartung, which was in a very sorry state due to the contamination

Source: Hot Hardware – GPU Teardown Shows Why Liquid Metal Is A Bad Idea On Aluminum Heatsinks