To be able to turn to white suit back to white which was previously turned
to white after fading first you will need to soak
the suit in clean warm water
and with a mixture of a strong substance such as oxide clean which is one of the best detergent to retain your clothes white color.
Another way is that you can decide to
soak it by the use of chlorine bleach but
this may require you to soak it for
up to a period of one or two days before the initial washing.
soaking will indeed ease the stains and later you may be able to wash it with ease.