If your Imamu is low on spirit or don't have any left, you can use shillings or soul shillings to rechage it!(Imamu also gets spirit when it lvls but it goes a little slow)
Press "n" to open the page of your imamu
Click the rechage button and then add the amount of shillings you wish to add!1c shilling = 1 imamu spirit
Then you press confirm and your done!