First of all 400V Caps have quite a bite to them if you touch one that is charged with more than about 90 volts... Anything above 48 volts you might feel depending on how moist your fingers are.
Secondly you want to stick with the same value capacitor and same type.
*Removed info on ways to make values with multiples of capacitors* Avoid doing that at all costs its too dangerous especially with the circuit your messing with which is probably a power supply or a flash for a camera which uses capacitors like this.
Whenever I work around high voltage capacitors, I avoid touching the PCB and any traces, and I take a digital multimeter to them. If a multimeter isnt available, with power unplugged
I have shorted them with a screw driver before after the device hasnt been plugged into a battery source or outlet for about 10 minutes to give it time to drain. Not all capacitors drain out quickly and so I short them with a insulated screw driver between their 2 legs only and not to anything else, and usually get a small spark where it might still have a charge and sometimes nothing so it drained safely. You reintroduce the screw driver to short the capacitor until sparking stops and its drained out as for your reaction might be to jump back if it sparks and that might be only a partial drain time from momentary short.
BE VERY CAREFUL WITH THIS CIRCUIT IF YOU MUST FIX IT The correct component with Radio Shack gone can be acquired online through Mouser, Digikey, or another source. You also want to look for the temperature rating on that capacitor such as 85C and match that too.
The typical temperature range for aluminum electrolytic capacitors is –40 ºC to 85 ºC or 105 ºC. Capacitance varies about +5% –40% over the range with the capacitance loss all at cold temperatures. Capacitors rated –55 ºC generally only have –10% to –20% capacitance loss at –40 ºC.
One suggestion I have is ..... Its likely safer to just buy a new of whatever this capacitor goes to as for the risk of injury or death by electrocution or fire is present.