Wire brush and/or fine glass paper. Coat with petroleum jelly only after a secure dry contact has been made.
Check your cables for corrosion; if there is any,clean them or replace them. Clean the connections at the starter and clean all grounding wires; test the starter regardless if you think it is good. Clean the battery terminals.
Bad connectins at battery? Clean connections. Possible loose battery cables on starter or engine block? Clean and tighten cables. If no help, possible bad battery cable/cables. Test cables and replace as necessary. Depending on what type of car, also investigate starter cylinoid. Hope that helps.
When one takes a look at a wiring diagram for Ford F-150 starter, one will see battery cables. Make sure all cables are clean and tight. Also, make use of a multi-meter to trace the power and to find the problem.
Double check the battery cables at the battery and at the engine, be sure they are clean and tight.
Without continuity they would not conduct electricity so as electric cables they would be a non-starter.
If the battery tests good and battery cables are clean and tight at both ends and you are jumping the starter solenoid correctly with no results, you probably have a bad starter/solenoid.
That depends upon what the starter problem is. If the battery is exhausted, you can use another vehicle's battery, with jumper cables.
First replace the cheap part, the starter relay. It is attached to the short positive battery cable; clean cables too. If no luck and your battery is good, replace your starter with a remanufactured one; don't try to fix an old starter.
Check the cables that go to the starter, make sure they arnt disconnected and they have good clean connections. Check the battery terminal connections to make sure they are clean and not corroded. Check starter relay switch, normally near the battery, it may need replacement.
Bolt the starter into the starter position. There will be three starter retaining bolts. Connect the cables to the front of the starter.
If you are 100% sure that the battery is good and all the connections are clean and tight, then you need a new starter. But make sure all that is okay first. does it have the right starter on it to start with? Have you been working on the engine and have it out of time??
I would assume u cod use a Paint for plastics thAt would infuse with your cables and be successful just clean very well and don't use acetone it might eat cables