At DESY activities on surface treatment of superconducting RF gun cavity resonators at 1.3 GHz are ongoing. Due to the small opening on the endplate for insertion of cathodes, no reasonable acid flow can be realized with the existing set up for horizontal electro polishing. To benefit from electro polishing of Niobium surfaces, an adapter to the existing horizontal electro polishing bench at DESY was set up and is in operation now. Vertical EP was applied on 1.3 GHz SRF gun resonators with 1.6 and 3.5 cell geometry. Work flow,process conditions as well as test results of gun cavities treated so far at DESY are described
