Second Laundry Cycle With Vinegar??

[Bionicle5]

After the first laundry cycle with detergent my mom does a second one with vinegar. Could some one explain the purpose of the second cycle with vinegar?

[satprof]

She uses about a cupful of white (or ‘spirit’) vinegar, which usually says 8% acidity on the bottle.

[windywillow]

Thanks prof.

[roopower]

I did read that in time vinegar corrodes the metal but perhaps thats if you put a lot in.

[TheWinner]

vinegar gets rid of excess soap.

[Bionicle5]

Yeah I think it's that one.