Rydberg atoms are highly sensitive to external electric fields due to their exaggerated electronic properties. This unique feature underpins many of their applications in quantum science. However, uncontrolled stray electric fields can be detrimental, severely degrading quantum control. In this work, we demonstrate a novel scheme that efficiently creates an in-vacuum charge source by photoionizing laser-cooled atoms and eliminates detrimental electric fields in a Rydberg-atom tweezer array platform, using only readily available resources. With this method, we began with Starkionized Rydberg continuum spectra caused by a large, unknown stray electric field of more than 10 V/cm and ultimately recovered well-resolved coherent excitation of individual Rydberg states after eliminating the residual field to an upper limit of 20(1) mV/cm. Our method applies directly to existing Rydberg-atom platforms and other experiments sensitive to stray electric fields.