How do you clean tank/items that were in contact with a sick betta?

[ktlelia]

I need to know how to clean tank and tank items that were in contact with a sick betta that passed away; whether to just toss things I cannot reuse or ways I can safely clean to reuse once again. (This betta, Rosemary, I do believe died form a really really bad case of SBD, but I may be wrong for all I know.)

Rosemary was recovering and passed away in my hospital tank which had a heater, thermometer, silk pants, and a coffee cup she loved. No gravel in this tank. I have no idea how to properly clean a heater or a thermometer. I don't plan on reusing the coffee cup at all, but I would like to reuse the plants if possible. I also have a fishnet that was in contact with this betta's water.

Also, before my Rosemary got sick, she was sharing a split tank for a day with my Izabella. Izabella is fine, looks fine, and is normal- however should I be cautious and do a 100% cleaning on her tank just in case the new girl left anything behind that may harm Izabella? Someone on here told me not to worry about it cleaning Izabella's tank, but I honestly think it would be stupid of me to just assume it'll be fine. I may just be still bitter or scared since Rosemary's death for all I know.

Sorry if these are stupid questions- I've never had a betta get sick on me and die. I've luckily only dealt with old age deaths with bettas in my betta care experience.
Thank you.

[whatsupyall]

SBD, I believe, is not contagious. However, as for cleaning, I usually just use hot water with white vinegar. I have used bleached in the past too, but I find it safer to use the first method. I usually rinse about 5 times and fish seems to do fine.