Arggh - housesitter and burnt on deposits on the burner rings (hob). Skanky cah!

[hmcAsWas]

So the house sitter doesn't seem to clean the cooker hob after use and lets food deposits just sit there and burn on to my formerly spotless burner rings (sobs)

How do I get it off? Doesn't shift with warm soapy water and a scourer

Thanks - will try that. Fingers crossed!