Euthanasia is a serious matter and should only be performed by a qualified veterinarian. It is illegal and inhumane to attempt euthanasia without proper training and the appropriate tools.
If you are experiencing a situation with a rat that you believe requires euthanasia, please contact your local veterinarian or animal shelter immediately. They can provide safe and humane options for your situation.
Remember, there are often other solutions, such as rehoming or contacting an animal rescue organization. Please reach out to the proper resources for help.