怎處理汽車水撥變硬?

用水磨沙紙(1000度)，輕輕磨下 d 膠就得。因為水撥加塵再暴曬，便會變得唔平滑，撥玻璃就會有聲。磨下佢，然後用濕布抹多次，無左 d 塵就會平滑返。用幾年都唔洗換。

買新啦. 好平之嗎. 因為用野軟化只是治標不治本.

水撥膠變硬，是因為紫外線之光合作用使然，如已變硬，就應更換。在各油站士多及汽車配件店舖都有賣，只須配合長度就可。
樓上所說之硅油，首先不能阻止膠老化，令膠軟化只是錯覺。加上硅油容易吸塵(其實所有滑油都吸塵)，容易刮花玻璃。而且市面並不容易購買純硅油之產品，須知道，大部份化學油脂，都會分解水撥膠，令其溶化(所以錯覺以為其軟化)。除了肥皂液，任何化學品都不應用於水撥清潔之上。

To revive hardened rubber blades

Clean off the wiper blade with alcohol, and put a coat of super lube multipurpose grease. Let the blade sit for about 6 to 8 hours then apply another coat. The blade will absorb this grease and works like hand lotion on dry hands. Wash the blade with mild soap to remove the excess grease. This grease is also used on waterproofing gaskets for electronic connectors and gaskets for radio housings so it will not affect or deteriorate rubber like many other lubricants.

Bonus:

Don't forget to clean the road film off your windscreen with a good cleaner. Spray a fine film of furniture polish (any brand). After light polishing, the windscreen will be absolutely clean and smooth so the wipers will never chatter over it. I do this all the time. When rain hits the windscreen, it'll just run off. Marvellous finish. Guaranteed and proven success. Road film is an invisible layer built from dust and ultra fine dust particles from smog, fossil fuel etc. Regular cleaning is a must to maintain perfect visibility.