The trouble with liquid sprays like WD40 is that they  are wet and can attract dirt to clog shit up, try a dry silicone spray lube it quickly dries out but leaves a dry silicone reside that keeps the surface lubricated.
A word of caution, try not to get this stuff all over your paint work, it's bloody hard the get off and it's an absolute pain in the hairy botbot to try a repaint over the residue!
You can tell if there is silicone residue on your paintwork...... you get strange looking pin holes forming in your paint as it dries, the only solution when that happens is to remove all the paint layers down to below the silicone layer, a good reason not to use silicone polish too!

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