computer power supplies

Could 6 12 volt computer power supplies be put in series to get 72 volts?
Or use the 12 and 5 volt in series for each supply, and put 4 for those in
series to get 68 V?

The insulation strength should be enough for the higher voltage, but is
there any other gotcha?

This would be a good reason to scrounge old computers.

Elliot Burke