Gold is classified as a noble metal by virtue of its resistance to corrosion and oxidation. Clean gold is characterized by a hydrophilic and high-energy surface, but, despite its inertness, the clean surface gets contaminated with small organic molecules within a few minutes of exposure to ambient air. 1 In fact, the so-called adventitious carbon (AC) 2, 3 is ubiquitously present on the surface of inorganic materials, such as metals, 4–7 silicon dioxide, 8–11 or indium tin oxide (ITO). 12–14 This airborne contamination is known to form a layer that changes the wettability of these surfaces rendering them hydrophobic upon air exposure. 1, 15–17 Gold is widely employed both in applied and fundamental research (eg opto-electronic device fabrication, adsorption studies, electrochemical detection) and it is also a suitable material for gravitational waves detection (Gravity Probe B, 18 UV-LED, 19 and LISA Pathfinder20). The control of adventitious contamination is of critical importance for the above-cited applications, as surface cleanliness and uniformity are among the key requirements to obtain reliable and reproducible results. 21–23 For example. in ultra-high vacuum (UHV) environments, sputtercleaning via ion-gun bombardment followed by thermal annealing is used to remove organic contaminants to yield clean metallic surfaces. 24–28 Alternatively, thin films of pure gold can also be produced in-situ via thermal evaporation, 17 sputtering deposition29, 30 or e-beam evaporation. 29 If gold surfaces are processed at ambient pressure (eg used as a substrate for the deposition of thin film or for the adsorption of biomolecules, monolayer films or …