electrolytic capacitor
What you are trying to do fundamentally won't work.  The capacitor rating doesn't dictate the voltage, only at what voltage it will fail.

What you are suggesting is like cutting some beams under a 30 ton bridge to make it a 10 ton bridge so that 20 ton trucks will stop driving over it.  Reducing the strength of the bridge won't change who drives over it, only the consequences of what happens when they do.