When making pure-clay ware without elasticizes, plasticizers or petalite (an ore of lithium), some lids may naturally warp slightly during firing.  For this reason we check and mark those pieces with a pencil, with the mark running from the edge of the lid to the rim of the pot. This is a good reference for finding the best fit between the lid and pot.

Here are some answers to additional questions you might have:

1. Are products that have the pencil marks from the Regular Line?

Yes, we mark both the Regular and Alternate line.

2. Won’t the pencil marks eventually wash off? Then, I wouldn’t know how the lid should fit on that pot?

Yes, the pencil marks will eventually wash off, but before then:

a. With repeated use, ”heating and cooling” the pot/lid pair will help them settle into a certain best fit position.

b. When you see the mark fading, you can easily re-mark the same place with a pencil.

3. If the pencil marks indicate the exact position that the lid should be sitting on the pot, then other lids from other pots would not fit, correct? Meaning, only a specific lid will fit with a specific pot?

There could be other lids that fit the pan/pot, but in that given batch of firing, this pair was determined to have the best fit.