Нельзя отмывать в ультразвуковой ванне
https://www.meishuo-relay.com/info/cleaning-of-relay-45004646.html
Preferably a non-clean flux process should be used; in this case there is no need to wash the PCB and we recommend avoiding washing processes in order to protect the environment. If cleaning is necessary, certain precautions have to be taken:
Ultrasonic cleaning is generally not recommended as this can cause friction welding of the contacts and in addition it may cause coil wire breaks. If ultrasonic cleaning cannot be avoided, it is on user’s own responsibility and must be completed as quickly as possible.
For gold plated contacts ultrasonic cleaning is NOT recommended at all as this might result in cold welding of the gold contacts.
Do not clean dust-cover type relays and flux-resistant type relays by immersion.
Even if only the bottom surface of the PC board is cleaned (e.g. with a brush), careless cleaning may cause cleaning solvent to penetrate the relay.
Plastic sealed type relays can be cleaned by immersion. Use a Freon- or alcohol-based cleaning solvent. Use of other cleaning solvents (e.g. Trichlene, chloroethene, thinner, benzyl alcohol, gasoline) may damage the relay case.
Cleaning with the boiling method is recommended. Avoid ultrasonic cleaning on relays. Use of ultrasonic cleaning may cause breaks in the coil or slight sticking of the contacts due to the ultrasonic energy.
Do not cut the terminals. When terminals are cut, breaking of coil wire and slight sticking of the contacts may occur due to vibration of the cutter.