Youre welcome. Its all about how much you want to tumble at a time and for how long. I've been tumbling rocks for decades and tend to do probably $60-70 in coins at a time. Add in the water and the total weight means I need a pretty good tumbler. I've seen some homemade tumblers that work fine. Obviously it isn't rocket science.
fwiw, I use water + a dash of soap. My coins don't have to pass the eye test, just the machine test so color doesn't matter(tho I do tumble pennies separately). If they are REALLY grungy or have calcareous concretions (beach coins), then i'll use an abrasive appropriate to the load. Theres no reason to add abrasives to circulating coins except to cut down on tumbling time. If you use silica sand (beach sand) then keep an eye on them cause it'll wear them down Quick.
fwiw, I use water + a dash of soap. My coins don't have to pass the eye test, just the machine test so color doesn't matter(tho I do tumble pennies separately). If they are REALLY grungy or have calcareous concretions (beach coins), then i'll use an abrasive appropriate to the load. Theres no reason to add abrasives to circulating coins except to cut down on tumbling time. If you use silica sand (beach sand) then keep an eye on them cause it'll wear them down Quick.