How can I get rid of Jarate?
Instant Removal
- Resupply cabinet
- Going underwater
- Ubercharges (it clears effects like jarate, fire, milk on the target)
Expedited Removal
- Standing by a dispenser for a while
- Getting healed by a medic over time
Getting healed by a medic or a dispenser removes Jarate very quickly, according to the TF2 wiki.
Unconfirmed accounts suggest jumping into water also 'rinses it off' ;)