Now there are many items on the market which replicate NMF really well - products such as Alcad come to mind. However I have found the easiest (and cheapest) method of making a decent bare metal look is to use car spray paints. Halfords do a can of 'Aluminium' spray paint - this is near-as-makes-no-difference a match to Humbrol 11 (allowing you to retouch areas with the brush if needed) but is harder wearing and easier to polish once cured.
The Fury does not have 'Natural Metal Finish' as such - most of the surfaces are painted silver and the only bare metal is on the cowling ahead of the pilot. However in the flesh it looked every bit as shiny as an aircraft with bare aluminium - so the same techniques would still apply.
The 1/48 Hawker Fury below is the good old Airfix tooling - a bit rough round the edges and requiring some work to fit correctly due to the age of the plastic. After dusting on a light coat - it was then given a second heavier coat to finish the model. The wings and fuselage were then buffed with cloth and cotton buds.
The real thing below.
Same method of Halfords rattle cans - this time on a few different models in 1/72 scale. Note that the P-51 and Vampire were 'weathered' using a thin brushed wash (didn't quite work according to plan admittedly) - hence the duller/streakier finish.
A word of caution however - make sure that whatever primer you use is compatible with the spray paint you intend to use! Don't ask me how I know...
