I was a cashier when i was 16 until i was 18, after that i worked in a shop where I had to sell jewelry. When I had a huge stutterblock I just said something like "I'm sorry, i have a stutter", and when the block was too heavy I just said "sorry" and tried to carry on the conversation in a different way (like using another word or talk about something else) At first i died every time on the inside, but after a while I didn't really care about it. That's when my stutter became a lot less tbh