You can always saturate your hair with water, add lots of deep conditioner, some oil on top of that (grapeseed, olive, almond, olive, etc.) , and then sit under a hair dryer for 30 minutes. That should make it easier to penetrate the hair shaft. I've never used baking soda, but I love acv for removing buildup. I also use Suave Naturals shampoo as needed which has a sulfate in it - not sodium lauryl though.
3b/c, medium-coarse, low porosity, high density
HG: Jessicurl Too Shea and Kinky Curly Curling Custard
Shampoo: nonsulfate shampoo and Suave Naturals sulfate shampoo when needed