Vfd 5 years in storage capacitor reforming?

[the great waldo]

Hello
I've got 3 vfd's A hitachi wj200 5or 6 years old and a couple off Huanyang VFD's all 2.2kw about 3-4 years old. All have been sitting on a shelf. I was wondering if the electrolytic capacitors might need reforming by using a variac to slowly raise the voltage to the units ?

Cheers
Andrew