Disgusting Slime vs Troll Snot Green

How close are they?

ΔE 29.3, loose: different enough that you should pick on purpose. Troll Snot Green is much more muted, cooler than Disgusting Slime.

Can I use Troll Snot Green instead of Disgusting Slime?

Not as a straight swap; see the closer alternatives below. Loose match (ΔE 29). Troll Snot Green is much more muted, cooler than Disgusting Slime.

Can I use Disgusting Slime instead of Troll Snot Green?

The same difference applies the other way round: Disgusting Slime is much more saturated, warmer.

ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.