Astrophysical sources of neutrinos have unique properties that allow us to investigate scenarios beyond the standard model that we may never be sensitive to in laboratory searches on Earth. As we begin to approach the high-statistics era of neutrino astronomy, our ability to extract new information from these observations will inevitably improve. I will cover how, in previous work, we were able to exploit the low energies and long baselines of solar neutrinos to obtain future sensitivities to the possible pseudo-Dirac nature of neutrinos at the JUNO experiment. I will also go through my more recent work on using point-sources of astrophysical neutrinos at IceCube to produce constraints on neutrino secret interactions.