Hi Froggies,
here are some handy tips that might be useful.
When cleaning flex connector contacts like those in a CX instrument cluster, try using a typewriter rubber . It cleans the contact without damaging the plating.
Recently when I removed the cooling system header tank I found a crack in the neck where the hose connects. Although it was not leaking it was a weak spot.

By using a hot soldering iron I melted the area of the crack. I clipped off some spare plastic material from the bolt hole support areas, and melted it onto the melted crack area to re-inforce the join.

I used the same method to repair the washer bottle as well.