1919 wheat penny with a weak strike on the R in trust.....is this considered a error of missing the R or is it just a weak strike and damage....
I've always enjoyed finding grease filled characters. I found one with a nearly missing T last year: https://www.cointalk.com/threads/1941s-lwc-grease-filled-t.384888/ Maybe they're not of sell-able value, but worth holding onto IMO. Nice find!
When the equipment is being serviced, they use an oily rag to wipe the equipment and the excess oil can fill voids in the die, causing the metal not to spread into the die properly, thus missing details. It is usually referred to as a "grease filled die."
I always find filled dies interesting even if they're minor and add no extra value. Absolutely nothing wrong with keeping it if you like it