RFI mitigation is a critically important issue in the development of next-generation radio telescopes including the SKA. Most designs for the SKA involve multiple stations with spacings up to a few thousands of kilometers and thus will need to deal with RFI environments drastically different from that of conventional single-station telescopes. As demonstrator observations and analysis for the SKA-like instruments, and to develop RFI mitigation schemes that may help in the designs of the SKA, we recently conducted simultaneous observations with Arecibo and the GBT. The observations were aimed at diagnosing RFI and using the uncorrelated RFI between the two sites to excise RFI from several generic kinds of measurements such as giant pulses from Crab-like pulsars and weak HI emission from galaxies in bands heavily contaminated by RFI. This paper will present observations, analysis, and RFI identification and excision procedures that are effective for both time series and spectroscopy applications using multi-station data.