If you are interested in darning, don’t worry if you don’t have a darning mushroom or darning egg. Anything that has a solid flat, or slightly rounded, surface can be used. As long as it will fit the thing you want to darn. For example, I have seen people using tennis balls which would work for darning socks, but obviously a football would way too big. And quite cumbersome to hold. So, something that would fit (into) the thing you want to darn and that you can also hold in your hand.
I have also seen people mention lightbulbs as an option, but maybe it’s just me, I wouldn’t feel comfortable using that. What if you accidentally held it too tight and it broke.
But a small jar would work!
Like this little jar, I think it had sundried tomatoes in it, but obviously the original contents are irrelevant! A small jam jar or a spice jar would work too.
What I especially like about a jar is that the gap between the jar and the lid is perfect for the hair elastic I like to use to keep the tension of the thing I am darning. You can just see the lilac elastic in the top picture.