Best way of cleaning nozzles?

[Roberts_Clif]

Here are my suggestions

I have PowerSpec 3D Pro (Flashforge Creator clone) with Swiss Micro all-metal hotheads.

Search web or E-Bay for "PowerSpec 3D Pro replacement parts" you can visually compare to see obviously mismatched parts.

Can heating cartridges and thermocouplers go bad?

Yes all consumables can go bad.

I don't have a thermometer with touch probes.

I purchased the ADM02 AutoRange Digital Multimeter from E-Bay work great, for testing temperature of hot-end and bed. It can measure voltage, current, resistance, diodes, transistors and continuity. This is a great bargain for a low cost.
https://www.ebay.com/sch/i.html?_fro...ADM02&_sacat=0