to measure a baseball glove you take a cloth measuring tape or piece of leather lacing or anything that won't stretch,,,make sure you "keep the tape or lacing touching the leather surface "of the interior side...
use a cloth measuring tape or a piece of leather lacing ,something that won't stretch to find circumference ,, lay the catchers mitt face down on a flat surface and measure the distance around,,30-32 inches is...
When it comes to conditioning a baseball glove Do Not use glove oil,.. baseball gloves that are saturated by applying any liquid type of "oil" make the glove or mitt almost twice as heavy and the leather will...