This is what i do, and it only takes 5 minutes TOPS, and u get a spanking clear diffuser.
1. I get a syringe... (if u dont have one, u should get one... they are awesome when dosing or spot treating if u ever need it...)
2. I attach a little tubing to the syringe and diffuser directly.
3. I pour a little H2O2 on the ceramic disk, and then i use the syringe to apply vacume so i pull the H2O2 though the disk.
4. I pull the syringe... fill it with H2O2... reattach it to the hose.. and then apply pressure to force H2O2 back though the diffuser onto a clean napkin to absorb the H2O2.
5. I repeat the vacuum and pressure with H2O2 until i notice its easier to feed the H2O2 into the diffuser.
6. Then once im done with the H2O2, i repeat a couple more times with Distilled H2O to force any left over H2O2 out.
Then my diffuser is about brand spanking good as new in less then the time it would take for you to soak it in anything.