Eliminating leeches: How?
Delete them. If you don't feel like doing that: ask why the card exists.
When you understand that, and inevitably where it is meant to be applied,
you can reformulate it to reflect more natural cues and answers, thus,
hopefully making it not a leech.
How do you eliminate leeches for language cards?
Delete them. You could use mnemonics but the chance a card is worth that
kind of time in language learning is low. You'll re-encounter the word or
structure later when it can fit into your head more coherently. Unless
you're at the start and nearly everything is unbearably hard.
What do you do if you're memorizing things that are unbearably hard?
Break them down. A lot. If it's a kanji, memorize the individual radicals
and combinations and build understanding of the whole from those pieces. If
it's a complicated word, and you really can't delete it, memorize the two
halves seperately (really).