I've been using cedar mulch for four years. It does nothing to repel slugs in my landscaping beds.

put wood ash around the borders in a thin line, they wont cross, also beer traps or oil traps (cups of the liquid) they try going for a swim and drown

TXEB is right....cedar mulch does not repel slugs.

The internets lied to me! I thought everything I read on the internet was true :P

That clears that up, then. I might as well stick with the cypress.

Two things I found worked well for me, and after a couple of years, no more slug problems:

1. Diatomaceous earth - sprinkle it around the base of plants to be protected. Will need to be replenished after rain or irrigation.

2. Sluggo - it's a safe bait that works.

Beer traps also work, but I found them a pain to keep up with.

beer traps get expensive, if i need some i just used leftover oil from frying

Slugs are attracted to the yeasty odor that stale beer has. A six pack of a pretty cheap beer that will last the whole gardenign season is less expensive then one container of Sluggo.
The fat in leftover oil would be far more likely to attract flies than slugs or snails.

ive only gotten a few slugs at a time, but we dont have a problem with them, just those tiny flies and only a couple

The question has nothing to do with slugs.

What? Of course it does.

<This is the Central Scrutinizer. We have another breakthrough human. Gardengal48 suspects the alternate universe. This is the second one this week.>

<Central, this is Rover 37. Breakthrough case will be dealt with same as the other one.>

<Roger, leave no evidence, too many are beginning to suspect.>

<Roger. Over and out.>