I would love an A4000, pricey though! IF you can find one..
There's tuts online for cleaning the heads on floppies for the Amiga so should be the same for the C64, just be careful.
The A4000 is lovely. Owned a 030 version of one for a while (1993-1996). The 060 Tower was it's replacement that I bought in 95. Weirdly, mine is an Escom machine but had a Commodore branding on it.. Possibly just using whatever parts were available at the time.
The 1541 is fairly easy to clean, just couldn't be bothered. Will probably do a full service, clean and lube it when I do get around to it. Although, I am very tempted to get a SD2IEC and just load everything to SD card.