This is going to be a collection of tips for you so to use about cleaning, maintenance and inspection of your multimeter test leads and test leads cables.
The goal of cleaning is not just about removing grease and dirt from those finger guards and cables.
Correct cleaning will restore even the performance of continuity mode, and will improve the responsiveness of the multimeter it self. Even when you get bright new test leads, or even these which came with your new multimeter, even those are not 100% ready to be used right away, a bit or preparation and cleaning it must to be made.
Within the manufacturing process, test leads naked surface is possible to be covered by soft oxidation or dry oil or wax, their electrical conductance is not 100% good at their side surfaces and this needs cleaning by Isopropyl alcohol and a ball of cotton.
Another good suggestion for a new multimeter is it banana inputs this to be cleaned too with Isopropyl alcohol and a cotton stick.
This will totally remove dust and particles that they did hide in those holes at production process.
For used test leads you may give them a good bubble bath with dish soap in liquid form.
Be careful to not soak the banana ends for too much time.
This washing time must be less than five minutes, and with soft sponge and the bubbles to gently work over the dirty surfaces.
After finishing with this bath, dry your test leads quickly by a dry cloth, then let the dry at room temperature for an hour.
Now perform cleaning of probe tips with by Isopropyl alcohol and a ball of cotton.
Wait for another minute so the alcohol to evaporate.
Now that everything is clean and shinny, it is time to inspect the cables centimeter by centimeter all the way from the one end until the other.
We are looking for any signs of scuffed insulation, or peeled back or cut to the extent that the inner white sleeve that is the isolation of copper cores, this seems now visible to us.
Test lead wires which do not include this second layer of white sleeve must not be used professionally.
Since 2010 is active this measure of protection which helps inspection about test leads damage, nowadays all serious vendors are now following and respecting this safety directive.
My advices are simple to follow and execute and therefore no special pictures are needed.
An last piece of advice if your test leads accidentally engage in low amperes sort circuit and they look smoked, an work around is to clean them by using a fiber Class pencil, this has a fiber class brush and this it will gently remove any carbon deposits from the surface of your test leads. http://www.ittsb.eu/forum/index.php?topic=27.0