| | Re: non-specific binding - IgG
I assume the IgG is there because these are IP samples?
If your protein of interest is common enough to have multiple antibodies available, you can use antibodies from different species for the IP (and whatever's already bound to the cells) and for the western. For example, use goat Ab for the IP, then use mouse primary Ab for the western. Then your secondary will be anti-mouse, and it won't react with the goat antibody in the membrane.
I've done this when looking for IP'd proteins where we already happened to have multiple antibodies on hand, and it works great.