Producing transmission grating using ion beam writing is known to deposit charges into the remaining material. This becomes an issue if you are diffracting polar molecules through such masks as the stray fields lead to random phase shifts, washing out the diffraction pattern [Knobloch et al., Prog. Phys. 65, 1600025 (2016)]. In our latest publication, we build on our previous results and show how the amount of implanted charges can be reduced to study molecules that were out of reach before.