Top Tip!
Put your top through the wash as usual, don't have to do this first but it all helps.
Buy cheap thin bleach for about 70p a bottle. Pour a capful or two in a half a bucket of hot water (5-10 lites) water and steep your newly washed top on it. Leave for half an hour to an hour but do not leave in overnight.
Rinse out with cold clean water and then bung the top back in the wash.
It should stay sterilised for a few more rides and washes before you need to do it again. Alter bleach concentration and frequency of steeping until you're unsmelly and happy.
This worked with the stinky tops I've done it to (endura and gore) and it doesn't seem to ruin the colours, but test a patch first if your not sure.