a realistic looking shade and render

[Ehsan_Fanian]

i want to shade a pepper in maya 2018 and ARNOLD 5

i already have texture for specular , specular roughness , color base and displacment map but i want to overly some smudge and dirt on top of it

can someone kindly help me out

what should i do

thanks

[Mr.baiking]

aiMix shader is for that purpose ,it can mix two shader with a mask

[lee_griggs]

You can also connect a smudge/dirt map to the Specular Roughness (via a Range shader for more control).