Would an external fuse holder with a battery ac oss the leads to get an amp or two across suffice?Household alkaline batteries would at best only last a few hours when supplying that much current, and in many cases less than an hour. Also, you would need to have a resistor in series, to limit the current to an amount that is appropriate for the rating of the particular fuse, taking into account the internal resistance of the particular battery.
What might be reasonable to consider is using an AC-powered power supply, providing some reasonably low output voltage, wired to a suitable fuseholder in series with an appropriately chosen resistor. In the case of a rail fuse (that would be conducting DC within a component) a power supply providing DC on its output should obviously be chosen. In the case of a mains fuse, though, in the absence of a detailed technical understanding of what changes occur during the breakin process that are audibly significant (or even of how these fuses work their magic) I have no idea as to whether it would be best for the output of that supply to be low voltage AC or low voltage DC, or if it would make any difference either way.
Regards,
-- Al