Did mine with wheel acid and a scotchbrite pad. Followed by a coat of wax. Current fleet
2011 Discovery 3.0 sdv6 XS
2008 Range rover sport HST tdv8*gone*
2000 Porsche 911 Carrera 2 convertible
1996 TVR Chimaera*gone*
2004 Vauxhall combo van*dead*
2003 ford ranger double cab

That's a couple of harsh products to attack the steps with, but if it worked for you  ON THE WAY: BMW F21 M140i
MERCEDES GL350 - Metallic Navy Blue w/Grey interior

GOING: BMW F31 335D MSport+ xDrive Touring
GONE: Land Rover Discovery 4 HSE - Stornaway Grey w/Black Interior (wish we'd kept it )
GONE: BMW F10 520D MSport - Carbon Black
GONE:MY12 RRS SDV6 HSE Sumatra/Ivory/Grand Black Privacy glass

It's two weeks old now (to us anyway) and has just had its second bath

Yep you guessed it doubt I'll keep that up

But seems ill get chance to try buff them step up a little tomorrow 2010 RRS HSE 3.0 tdv6 2010MY
2012 Audi a5 2.0 tdi s-line
2005 Discovery 3 tdv6
2009 audi a4 2.0tdi saloon
2007 Audi a3 1.9tdi sportback
2004 Navara Double Cab
1996 Shogun 3.0 v6
1984 Landrover 90 2.5d