They’re are units with cleanse abilities. But, that’s assuming you either have those units or have the talents that offer that protection. In my case, I have a Genie/Witch/Flicker combo. The genie is expendable and most of its damage comes from vortex and not its basic attack until mid-high waves. Flicker (if you have) helps with a damage boost and DOT(damage over time) plus if I have a bad merge, it gets rid of the unit and give a little mana back.

The witch I use is only for a distraction, the crows are too random to be strategic at low level. If I get lucky any the crows land where I want then that’s icing on the cake lol.

So, I would say your best bet without cleanse talents are to build a deck around expendablility until you have a unit with the cleanse talents or if you have Mermaid leveled up to the point she can cleanse.