Silver coming out with black grease/scum

I'm using a Lortone tumbler (relatively new barrel) with mixed jeweler's shot, small pinch of burnishing compound, and enough water to cover shot and jewelry plus about half an inch. Usually it works great, but recently I'm having some problems with sterling silver pieces coming out with a thin film of dark grease. I tumble for an hour to two. Any suggestions or hints? It would be very much appreciated :)

Cheers, Griff

Stacy's Answer:

Hi Griff!

It sounds like your shot and barrel may have been contaminated by what's been put in it. Burnishing compound is great for some items, like shiny components that need smoothing and polishing, but not for oxidized or etched items. There's nothing to hold the "gunk" being removed from the metal in suspension, so your tumbler is just depositing it right on the metal...including the shot! After a just a few uses, you can acquire quite a build-up!

If you have put etched items in the tumbler without making sure that the etching solution was neutralized and thoroughly cleaned off the metal first. Traces of the etchant can have disastrous results on the items tumbling, including the shot. First clean your rubber barrel with warm/hot water and dish-soap using a sponge or paper-toweling - not an abrasive scouring-style pad. Next, clean your shot. You may use either a shot cleaning compound, or flat coke with a squirt of dish-soap.

Once your shot and barrel are clean, you are ready to add items to it. Place them in the tumbler along with the shot and add water to about two inches over the items. Normally, I add water to only one inch above the jewelry or items I'm tumbling. Then add a healthy squirt of dish-soap. Smaller batches of jewelry will clean more evenly allowing the shot to make contact with all the surfaces. Tumble for only about 2 hours, then rinse and refresh and repeat if necessary.

I hope this works for you and that you'll soon be getting great results from your tumbler!

Comments for Silver coming out with black grease/scum

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Aug 11, 2012
Same problem as Griff
by: Sarah

Hi there,

I had the same problem as Griff. I called Rio and they suggested cleaning the shot using the flat coke. Then I ran the tumbler with my silver and soap and water and it didn't come off after hours of tumbling. Any suggestions?


Dec 16, 2013
getting the scum out.
by: Anonymous

I had the same problem- Lortone must have had an iffy batch of barrels. I think they are made of polysulfide rubber. I scraped out the inside of the barrel with a metal scraper and cleaned it very well with hot soapy water. Sometimes it can also happen if fluid is left too long in the barrel. I think the burnishing compound is also very harsh on the drum so I don't leave it in the barrel more than an hour or two.

May 21, 2015
same problem as Griff!
by: Sui

I had that same problem with the dark, sticky gunky stuff on my sterling. I think it's from the barrel. Im gonna try cleaning the barrel. Im thinking I left it in for too long ( an hour and a half) because the barrel was warm when I picked it up.

Sep 09, 2015
greasy gunk
by: Anonymous

I am having the same problem with the tumbler ruining my fine silver just-made jewelry. I've cleaned and cleaned with dawn water, etc, but the water is still a filthy black. Has anyone solved this problem? Do I need to order new shot, my 2nd order in less than 2 months, and a new barrel? my tumbler is only 2 months old.

Sep 09, 2015
Gooey Residue in Tumbler
by: Stacy

The burnishing compound may be an issue as the chemicals are sometimes incompatible with the rubber and sadly, you don't know of a problem until you use the burnishing compound. Make sure that you are diluting the solution as per the manufacture's instructions and it should be safe.

If when using only dish soap and water along with stainless steel shot AND the metal going into the tumbler is clean - no acid treated items like etched copper as the mordant, ferric chloride also etches stainless steel and the residue reeks havoc with your tumbling medium and barrel. Place metal in a baking soda/water or ammonia/water bath to completely neutralize it - and you still have a problem....

Then it's not the shot, but the rubber of the barrel that's the culprit. Bad rubber seemed to have been a problem from a few years ago and so this issue hasn't surfaced for a while. Replacing the barrel should resolve the gooey residue problem.

Sep 10, 2015
greasy gunk
by: Anonymous

thanks for your advice, but luckily, I tried tumbling shot with Coke, flat of course, for two hours. I rinsed everything and tumbled with water, overnight, and today all is well. last night's water was crystal clear and I'm ready to tumble jewelry again.
ps/ I love your bead caps.
have a fantastic week.
thanks for all of your help.

Sep 10, 2015
Greasy Gunk
by: Stacy

Yes, Coke Cola works wonders for cleaning dirty shot! Glad you didn't have a bad rubber issue as replacing barrels gets expensive.

Hopefully, you'll enjoy hassle-free tumbling from here on out! Thanks for sharing your results!!

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