Mixing G-gel with cwm is perhaps best mixed fresh, however, storing should be fine as long as you don’t allow the gamsol to evaporate. I store the mixture in candle tins with covers for longer term storage of pre-mixed quantities of G-gel/cwm. (Click here and scroll down to see the candle tins I use in my Resource section of www.ARTandSUCCESS.com)
*I use covered tins to store my Cold Wax Medium mixed with Galkyd Gel and it stays fresh for 1-2 weeks.