The handbook recommends 3in1 - "Annually". Do it both sides, either use a small paint brush or dropper.
I do it more often than annually, and have also used Tectyl 506.
Some are using ACF50 but there's a slight question mark about whether it softens the beading over time. But if 3in1 is OK, then ACF 50 may be OK.
ACF 50 is an aircraft service product. According to the producers website it has:
MIL SPEC 81309 TYPE II AND III APPROVALS which means ACF-50 is approved for ferrous and nonferrous metals, electrical systems and electronic components.So, if it can be applied to aircraft wiring it has to be safe with all plastics, never degrading them. My view is that applying it to the beading will protect it. I apply it to the beading every autumn and spring.
Actually, the only thing you shouldn't apply it to is the brakes and exhaust.
More information
HERE! Reading through the details it would seem that it should also inhibit galvanic corrosion between none similar metals, so the running board treads on trads and on Aeros where steel screws go into the aluminium body at the back, a known corrosion point after 10 or 15 years...
