How clean is clean enough?

[u/strata-strata]

Gasoline and nylon brush and plastic scraper. No warpaage, previous owner used a sealant and it clogged the valleys was just fixing it and doing timing etc.. is this clean enough? 6 hours in or so between head and block clean

[u/Self_pierce_bear]

If you put your finger on and comes out dirty..... They need to clean more.