removal of chrome from aluminum alloy

[amalventano at sc.rr.com (Allyn)]

ok, so the gas cap for the rieger is looking kinda crappy lately. its a 
sparco aircraft style filler cap, which is chromed aluminum. sparco stuff is 
usually good, but this chrome job is quite shitty. i need to know the best 
way to strip the chrome while keeping the aluminum in tact. i then intend to 
prep/paint it the same color the wheel centers were painted. anyhow, any 
chrome gurus around that can throw some advice my way?
thx in advance
Al

Allyn Malventano, ETC(SS), USN
87 Rieger Scirocco GTO 2.0 16v (daily driver, 200k, rocco #6)
86 Kamei Twin 16V Turbo Scirocco GTX (30% complete, rocco #7)
86.5 Occo 16v Trailer (rocco #8)
90 Passat GL 16V (the wifes new daily, 200k)