Citric acid can be plain white vinegar.
You can buy some small pet bedding(aka Lizard bedding) at a discount pet supply shop(great big bag is less than $20) put it and your cases in a plastic bucket with a secure lid and put the whole thing in your dryer for an hour or so. Think loud so you may want to go out.
In any case, making a tumbler isn't difficult. Really just needs to vibrate.
You can buy some small pet bedding(aka Lizard bedding) at a discount pet supply shop(great big bag is less than $20) put it and your cases in a plastic bucket with a secure lid and put the whole thing in your dryer for an hour or so. Think loud so you may want to go out.
In any case, making a tumbler isn't difficult. Really just needs to vibrate.