I thought I'd post this, as it is an example of a "worst-case
scenario" situation. A few months ago I acquired a rather high-end
Mitsubishi VHS VCR from eBay for not much money. The seller said the
VCR was in excellent condition, and very clean. I'm sure everyone has
heard this before... LOL. To make a long story short, when I received
the VCR it was an absolute disaster from a aesthetic and cleanliness
point-of-view. Obviously, the original owner was a heavy smoker, and
the VCR absolutely reeked of smoke, and nicotine stains were the worst
I've ever seen inside and out the unit. To put it mildly, it was
horrible, and I almost felt I needed to put on rubber gloves just to
touch it!

Strangely, it worked fine, but otherwise it was a real mess. So, I
decided to disassemble it and clean it manually. It didn't take long
to realize that this was hopeless. Thus, I did the
unthinkable,especially for a VCR. Once disassembled, I put each board
and the chassis/transport into the dishwasher taking care to cover and
protect the video head drum. No dish washing detergent, just the
water. After a full wash, rinse, and dry cycle, I removed it, and
gently dried it with compressed air, and then placed it into a 100
degree oven for a short time.

After 3 months, the VCR is still working fine, and it looks (and
smells) like new. Realistically, I had nothing to lose by trying this
worst-case cleaning method, but it worked. It sounds like this would
be an absolute disaster for a VCR, and I must admit, I am surprised
that it was successful.

I have used this method for cleaning other types of electronics in the
past, but not a VCR.