Prob best not to use electrical contact cleaner as its a bit "active" for a sensitive part like the wire. You can get a much milder MAF cleaner that still does the job.
Can I mention that on diesels that are not run very often and the fuel tank is not always topped up can get something that grows in the water and diesel and it will block filters and pipes.
Vehicles that are most at risk are things like horse boxes and such that go out for a drive and back and then stand still for a few weeks then go out again, a dumper only used a few times during the year? Very slow at using the fuel and it sits there, boats are a good point in the Marine trade it is a well known thing, but someone we know in the vehicle trade, could not work out why the his miss's Horse box would not keep running I mentioned this growth and he was able to solve it.
There are now fuel addatives that are suppose to stop it but you need to know about it first