cheap washes have anti-freeze/ethylene glycol and the good ones ethanol - and you don't want to mix the two - I now ensure I buy the latter.
further on the upgrading audio subject -
seems
there had been a helix device that could take the MOST interface optical feed from the hk HU as opposed to high level already eq'd&lified outputs from HK amp
(amps outputs also used for hi-fi&basic upgrades, so they are in same boat) but patent infringements on optical connectors meant they stopped production
=> if you want digital all the way to amp, need to feed upgraded dsp/amp directly by usb/optical from phone,