Also just call & even think of them as uncle or aunt soinso but know them as great uncle or great aunt soinso. Had about 8-10 each through mom's mother and dad's father so with so many 1st-cousins-once-removed and 2nd cousins, as a kid, I used to confuse some of my aunts & uncles for just more cousins.
Then they really screwed me up by introducing some of their dearest friends to me as aunts and even my cousins' aunts and uncles who weren't even related to me became my aunts and uncles. Mom instilled a very strong sense of family.
One time as a little kid one of the non relative great aunts picked me up and took me to Palisades Amusement Park for the day. I had no idea who she was and I could never remember her name. For the rest of my life until she died when I was in my 40s, she became Aunt Whatshername.
Another aunt--who was a very close sister to my grandma and our mother's were close and I was close to the daughter in my generation--so who was actually a great aunt to me, became for my entire life my aunt-grandma and that's what called her, I think because my grandma died when I was so young. She lived a long healthy life. Died in her 90s. RIP aunt-grandma.