dark spots on the soles of my feet

[2MUCH4066]

Hello I'm a Dark skinned black 40 yrs old female with HBP I take Inderal and Diovan 320/25. about a year ago I notices brownish black spots on the sole of my left foot about the size of a pencil earaser or smaller and 1 brown spot in the center of my right foot sole about the size of a nickle.  They are flat and circular and never itched, not raised, no bumps.  I have been to my primary doctor. I also went to a podiatrist  who stated it was nothing he said it looked like cafe latte' spots in which he states was no problem and would go away on their on.  I don't know what they are they are just unsightly but cause no problems.   No one can tell me what it is. I need some advice to at least tell my doctor or maybe some type of test to give me.  Can you get something to remove the spots off  the soles and around the heals also.  I don't have bad skin my feet are in good condition.  My job requires me to wear black boots five days a week and I have worn them for about 11 years straight.  Like I say the spots don't cause any problem I just don't like the way they look.  I was wondering is it some cream or liquid I can try.   I don't have any spots on my body just primarily on my left foot.  Thank you in advance