well your build up is probaly from using products on the no no list, so it would be a good idea do to one last sulfate poo to get rid of the build up, as for the products that you should be using, anything with no cones or sulfates, i personally like to use things as natural as i can. my fave is oil. bt lots of curlies use different things, its just a matter of finding what works for you

my hair: 3b, high porosity, high density and coarse hair (i think i finally figured that all out)
my hair loves conditioner only styling!
Oils and my own procuts are my hairs best friend
my hair goal length is bra strap length when curly.