How do I protect these markings on the stem when I give them the Oxiclean treatment?

[Haebar]

How do I protect these markings on the stem when I give them the Oxiclean treatment?

http://i1377.photobucket.com/albums/ah50/haebar/Cigar%20Bum%20photos%20006_zpsr5olfzur.jpg

Also, how much Oxiclean should I put in the soak water?

[cbr310]

I just did mine for 2 hrs had a white marking on mine. it didn't bother therm at all. put 2 scoops in a bowl.

[Branzig]

How do I protect these markings on the stem when I give them the Oxiclean treatment?

Place dabs of Vasoline over them.

For four stems, I'd use 1.5 scoops or so.