Just bought a Leader 1301 Function generator and was disappointed to find that all of the push button switches seem to be dirty. After trying multiple times I was able to finally get an occasional decent waveform on only a few the frequencies. The range buttons seem to be the worst while the frequency dial is clean, without any noise. The waveform buttons are also a problem but not as bad. My question is can I clean these with Deoxit D5? Or should I just return it (sold as “This is in good working order.”)?