I have 2 different 100nF capacitors. Let's call them A and B. My dad told me that B is "better" than A. I've tried measuring their capacitance using a Metex multimeter which has the option of measuring capacitors. I connected A and it showed 80nF and then it started slowly rising until it reached about 130nF. What's more, I've tried touching the capacitor (I was careful not to touch the terminals, I've touched only the coating). It influenced the result of the measurement - capacitance decreased. I thought that maybe it is related to the temperature but then I blowed warm air on it and it didn't change anything.
And then I connected capacitor B. It showed 100.5nF. I could touch it as much as I wanted and it didn't influence the measured capacitance. It was rock solid.
At first I thought that A is faulty but I have more capacitors of this type and all of them behave in the same manner. Why is this happening? Can I still use them e.g. as a Vcc buffer in an IC (like Atmega, etc.)?