Hi guys i was wondering if any of you can help me on this
my car porch granites tiles are turning yellow....

Some of the yellow thingy are dirt and dust... I have tried using scrubbing using soap..
but can only clean like 70% of it but the yellow dirt still remains



I tried using acid (the yellow colour one) and it can remove the yellow dirt but the nice granite surface is like gone already



the 2 tiles on the left are the original color.... the big tiles on the right is the one i use acid to wash..

can anyone suggest what is needed to use to clean this once and for all...