My physician removed the only one I've experienced when I was 12.
He removed the dead skin around the core, swabbed some salve on it and said in a couple of days the core would fall out when washing the wound.
3 days later it came out. A little encapsulated black pellet.
Also, working construction, having to walk long distances climbing over re-bar, concrete forms, mounds of dirt and debris as I got older I noticed the bottoms of my feet would ache about 1/2 thru the day. So, I took to wearing two pair of socks w/high quality insole inserts and the soreness went away.
I buy the insoles given to Diabetes Patients at the VA. Aetrex walking, running inserts. Amazon sells them. $20