Every day/when you want, write something as an offering to the deity/spirit on a small piece of paper. It could be words of praise, a song that reminds you of them etc. Anything, really. Then put it in the jar.
(Alternatively use small rocks or sticks and meditate while holding them, metaphorically infusing the words/mood of your offering into the thing.)
When the jar is full, use it in a ritual dedicated to the deity/spirit, or when asking for something. Maybe you’re asking for strength on a rough day or for inspiration to do well in a creative project. Or you’re just saying an extra big thanks.
Burn the pieces of paper or sticks, or throw the rocks in a lake or something – whatever (eco friendly!!) way of disposing the things you prefer. Metaphorically, you’re then reminding the deity/spirit of all your days of taking time to give something to them, and you’re letting all those little tokens go now to start refilling the jar again.
Or you could just let the jars be and let there be more and more of them on your altar as time goes by!
fair--y backup 