you'll definitely need to wash it!! Thereafter you can decide whether to continue using If you're not using distilled water it's because of build up from minerals (in tap water for example). I wash my steriliser parts (all the containers and trays) and also wipe down the heating part on a monthly basis
Oh dear.. im not sure if yours can still be used. But, normally, I use cooking artificial vinegar and pour it in my steriliser. I leave it in for 30 mins then scrub.
I never bother to sterilize any items while my gals were babies. Now, they are all super healthy and strong and they seldom fall sick. 😊
looks like it really needs a good wash. Personally I don't use steriliser as I don't c the need to