Tea tree oil is immiscible in any water-soluble chemical, and that would include glycerin. The TTO would just float to the top of the glycerin. That's why the polysorbates are in the commercial product -- so the TTO and glycerin become miscible or at least emulsified.
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I know this is about demodex not staph, but here's the best I could find regarding TTO use around the eyes -- from http://roberttisserand.com/2013/02/essential-oils-and-eye-safety/ ....
"...In a Chinese study, an ointment containing 5% tea tree oil was used by patients whose eyelash follicles were infested with “eyelash mites” (Demodex folliculorum). The ointment was applied to the lid margins with eyes closed, daily for 4 weeks after washing the face, and resulted in considerably less itching and fewer mites. Two of the 24 patients experienced slight irritation from the ointment. The 5% concentration was arrived at after preliminary testing using various dilutions on rabbit eyes (Gao et al 2012)...."
Gao YY, Xu DL, Huang IJ et al 2012 Treatment of ocular itching associated with ocular demodicosis by 5% tea tree oil ointment. Cornea 31:14-17. Read abstract...
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I know this is about demodex not staph, but here's the best I could find regarding TTO use around the eyes -- from http://roberttisserand.com/2013/02/essential-oils-and-eye-safety/ ....
"...In a Chinese study, an ointment containing 5% tea tree oil was used by patients whose eyelash follicles were infested with “eyelash mites” (Demodex folliculorum). The ointment was applied to the lid margins with eyes closed, daily for 4 weeks after washing the face, and resulted in considerably less itching and fewer mites. Two of the 24 patients experienced slight irritation from the ointment. The 5% concentration was arrived at after preliminary testing using various dilutions on rabbit eyes (Gao et al 2012)...."
Gao YY, Xu DL, Huang IJ et al 2012 Treatment of ocular itching associated with ocular demodicosis by 5% tea tree oil ointment. Cornea 31:14-17. Read abstract...