what's the difference between shampoo bars and regular bars?

[Nanditasr]

I don't make my own shampoo...
If I were you I would make a mix of 2 tsp of AC and 2 tsp of Glycerin or water and add 1/8 tsp of this mixture at a time...

I failed to notice in your earlier post that it's a shampoo you buy! Thanks; I'll try out your suggestion.