best way is to strip it and soak in Fairy Power spray - easiest is a touch up with paint tape. I've got Zero One Green off a Raider's RIS but it was a pain coz it was boated on. gave up on crane stock
TBH - it is a £100 gun or so - don't go too nutz on it unless you are sad OCD like moi. Touch it up, it will scratch but wtf it is still just a G&G 2-tone unless you go nutz
Some paint will come off easy like Airsoft World snake skin but Z1 is a bastid. Be a bloke, try not to worry about the look or colour like a tart & worry about how well the gun & yourself shoots