Most older Alfas have a clear coat on top, a respray is the only way forward to get rid of the pinking.
As said already, to slow it down you can either use a good sealant or wax.
I even spoke to a Meguiars rep and classic car restorer about this a while back to get first hand info.
a G3 cutting compound plus a good mop & polish was recommended but not guaranteed because of having a clear coat.
You can even try and get the panel done separately by a specialist body shop who will use a colour spectrometer on the nearest panels to get an exact match of the aged paint, it still wont be 100%.
Ask any paint specialist bodyshop and they will all tell you that a clear coat Red on any car is a nightmare.