One method I use is wet newspaper. Use it as a mask. Being wet allows it to stick and it will not pull up the foil when removing. Make sure it is good and wet, not damp. Use a paper towel or cloth to remove any water runs prior to painting.
Berny
Phormer Phantom Phixer 
On the bench
TF-102A Delta Dagger, 32nd FIS, 54-1370, 1/48 scale. Monogram Pro Modeler with C&H conversion.
Revell F-4E Phantom II 33rd TFW, 58th TFS, 69-260, 1/32 scale.
Tamiya F-4D Phantom II, 13th TFS, 66-8711, 1/32 scale. F-4 Phantom Group Build.