The only trouble we've had is getting the contractor to clean off
pointing residue promptly to avoid aggressive acid washing of the
slow-curing mortar.


Unfortunately this is the only method most of these morons know. This mentality of course comes from the cheap mass produced housing of today.  I'm sure they are using an almost soup consistency for the repointing mix. Are they using grout bags to repoint with and wire brushes to clean the brick?

Steve

Steve