need help interpreting DC readings

Hey all;

I'm trying to isolate sources of DC from my guitar effects pedalboard so I've cracked open a few of the pedals themselves to check them out. on the

1st pedal, I measure 0.1 mV on the output (measuring from cap to ground). It doesn't float around a bit 1st, it just measures 0.1 On the next pedal, the readings are all over the place. They range from about -2mV to +3mV, and constantly floats around, never settling. I figured the cap must be leaky, so I replaced it with a new metal film, but I get the same readings. I measured the next pedal, and I get the same type of reading where the DC level is floating all over the place. I haven't replaced that cap, since replacing the cap in the other pedal didn't seem to change things. in all 3 pedals, there is a 100K resistor at the output to ground. Given the new cap and the resistor to ground, how can there be any DC at all there?

Also, the inputs of each of the pedals show a DC level that starts out at around 350mV and settles down to 0.2mV over the period of about 15 seconds. Is that normal, or should I consider these caps leaky also?

Thanks