Spider and Blackhead are both incomplete dominants and allelic, and seem to do the exact opposite thing, so when combined they cancel each other. Albino doesn't cancel out Clown if that's what you were thinking, but it's very difficult to make double recessives.
For example, even if you bred a visual Albino to a visual Clown, not hets, and you get %100 double het hatchlings, when you breed those double hets together, you only have 1/16 chance of getting an Albino Clown, and you get a TON of Normal 66% double hets that are near impossible to sell if you don't have a strong reputation.