Take a pic. I'll bet it's an LC line filter. Could look like this
https://www.newark.com/te-connectiv...r-line-filter-10a-700/dp/52K4492?CMP=KNC-GPLA or other variations.
6 amps would not normally be on a capacitor.
FWIW. The product of R and C is what's called the time constant. And, FWIW, it takes about 5 time constants for a capacitor to discharge to 98% of it's value. That gives you a mechanism of selecting a resistor and time.
Measuring the voltage is OK as long as the rating is < 600 V. High voltage caps require more precautions.
The color code can be found anywhere, but you have to be aware that not all resistors follow the exact same code. Some use 2 significant figures and a multiplier and some use 3 sig figs and a multiplier.
It boils down to the following mnemonic "0-Bad (Black) 1-Boys (Brown) 2-Rape(Red) 3-Our (orange) 4-Young (yellow) 5-girls (green) 6-But (blue) 7-Violet (Violet) 8-Gives (Grey) W-Willingly (white).
To avoid the black brown discrepancy, you can substitute Black for Bad and get the raciest version. Then you have Grey and Green to deal with.
So, for a 4 band resistor having black brown red gold, you get 10 as significant figures and red is 2, so you add 2 zeros and get 1000 ohms, The Gold is 5%, Silver is 10% and no band is 20%, Brn black blk brn is also 1K and likely 1%. That brn can get confused with gold. So, even if you think you know the value, measure with an ohmmeter to be sure.
Power has lots of formulas: P=V^2/R would work for you discharge problem. You can use the voltage rating of the cap as V and R as the resistor, Use 5*RC = 10-20 sec and you can figure out what wattage resistor you need If P is 0.375, go to 1/2 Watt.
So, you can now select a resistor and the power rating and determine how long you should hold the resistor across the terminals.
It won't cover brown black gold gold, but they aren't too common.
Resistor wattage is based on physical size: 1/8, 1/4, 1, 2 , 3. and 5 Watts are common,
Special precautions exist for high capacitance like in Farads and high voltage. Very high capacitance is used for a back up battery. Very high voltage caps like for 10 kV do not discharge completely and will "come back to life" after being discharged.