Can I make a non-polarized cap from 2 polarized caps with different values
You can do something like this:







simulate this circuit &ndash; Schematic created using CircuitLab

Not all electrolytes will withstand the 0.7V reverse voltage: wet aluminum electrolytes should withstand at least -1V, do not try with tantalum capacitors. You can use Schottky diodes to get lower drop if you have some at hand.

Note that if C1 and C2 are different then this circuit will have capacity of C1 on one polarity and C2 on the other.