I know he's from Vancouver, hence my comment :) I like Steve Kaufmann too, his videos often contain useful advice about language learning.

thanks a lot guys:) he is actually from Vancouver. He tends to use various vocabulary, which makes his videos very interesting.

That is what he said, but I too have never heard this word used in that way before. I would guess that it's Canadian slang

As far as I can gather (which means the word is not a common one), "grubbies" are the clothes that you can get grubby. They're relaxed, comfortable clothes, but certainly not anything you would wear outside the house. Some other examples of "grubbies" as clothes refer to old clothes you would wear when you're about to do some dirty work.

Maybe I don't hear it correctly: https://www.youtube.com/watch?v=1QfWHAvFxnY I am a big fan of Steve Kaufmann. He says sth., like grubbies in - 0.58.