Disconnect the power before attempting any work. Use of an RCD (plug in power breaker) is recommended.
Take a piece of stiff wire or a screwdriver and start chipping away at the buildup until the hole is revealed.
If necessary remove the top cover of the machine,(power off) and disconnect the flexible hoses from the dispenser. Check if theyre blocked. The dispenser itself can be separated - generally held together with plastic clips. Clean out any crud or hardened detergent.
Repair and service your own washing machine. Go to www.2ndwave.co.uk/manual.html
dannyboy, October 2008