extraneous

Not belonging to, or dependent upon, a thing; without or beyond a thing; foreign.

to separate gold from extraneous matter

Extraneous substances were found on my cup of water.

Not essential or intrinsic.

Edward had seen beauty often, and seen it with every possible aid; but never had he seen beauty so perfect, yet so utterly devoid of extraneous assistance.

If the Government believes that part of the railways' salvation is to be found in ridding them of extraneous concerns, it should have had the courage either to close the railway works down as quickly as possible, or to hive them off as an entirely separate concern, [...].