Philman is right, anything that is sterile, stays sterile only if you don't open it outside the hood. If your gloves are clean, there is no need to burn the edge of the beaker. Just try not to touch the remaining pipettes. The best way is to tilt the beaker and try to shake it gently untill one pipette slides out.
I know this question was not for me, but I can't remember any moment, when I put medium in a bottle, that was previously autoclaved. When do you do so?
We use sterile bottles, in which the media come, and single-use falcon tubes to prepare any solutions. As far as I remember, they are gamma-sterilised and are sterile inside untill you open them. The only thing that we autoclave before working with cell cultures are all kind of pipetes/pipet tips (they are single-use as well, but not sterile). Even if there is some water in the box containing pipette tips, it doesn't touch the tips, there is no way it can affect the concentration of reagents You measure. Only if some bacteria get into the box, they will grow better if there is water inside.
Bob1, thank you. I have always wondered if it's really so important.
Edited by EvilTwin, 09 January 2012 - 01:24 AM.