As far as scrubbing my new set of boots in I took it easy for a tank (~200km) and then took it up a twisty run. 1cm on one side and about an inch on the other now. At least now everyone knows which is my preferred side 
For cleaning tyres I've always just been careful when cleaning my chain. I use a toothbrush and have never really had an issue. When I'm spraying lube on I aim for the tyre not the wheel
If I notice gunk I just take it easy for a bit till I assume it has been taken off by friction.
For cleaning tyres I've always just been careful when cleaning my chain. I use a toothbrush and have never really had an issue. When I'm spraying lube on I aim for the tyre not the wheel