Did I understand correctly that you made these yourself from glass beads and stripped CAT5 wire?
Oops, you used cat3.
I bought a bag of 100 for EUR2.20 from ali.
Pre-made and they look gold plated, or at least yellow shiny instead of red copper which will probably oxidize more readily.
https://www.aliexpress.com/wholesale?SearchText=pcb+board+bead+test+pointAnother tip:
Sometimes I use a small resistor as a shunt for current measurement and I solder them directly on the target (vero board) PCB while designing. I also solder a 2 pin header with 0.71mm square pins parralell to that resistor.
Those are an easy attachment for "dupont" style cables (easy for breadboard, make an adapter for your multimeter).
This makes for a reliable connection, with no chance of temporarily opening the circuit because of a bad test clip.
And when not in use, or when there is doubt the shunt resistor may influence your circit you can put a standard jumper over it to short it.
Another tip:
On a lot of the experimental designs I make I make a large ground loop from standard 2.5qmm copper stripped installation wire.
Those are very easily recognized as a GND connecton to connect your oscilloscope GND probe and various GND clips for other measurement equipment.