| EEEEKKK WD40 ??
WD40 does clean the chain up nicely, but unfortunatley it dries out and perishes the rubber seals giving the chain an untimely death.
The safest way is to use parafin or diesel (both oil based) to clean the chain up, leave to dry and then i apply with a brush some ATF fluid (or a clean high quality fork oil - but ATF is basicly fork oil with preservatives and detergents added), wipe off all excess, then apply a thin coating of chain lube, again cleaning off all excess.
this tends to do me for about 1000 miles happily. But then i get over 14k out of a standard chain on my blade like this before its finish was shot from a good winters riding.
Also dont use WD40 on caliper pistons and seals, before you know it you will have leaking seals and very perished rubbers, again use either parrafin or diesel fuel and a toothbrush | 
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