Can anyone tell me how filter out amplitude spikes when recording from LP records/albums? These are caused by scratches or dust particles on the LP. I can’t see anything relevant in the Audacity Manual (under Effects or Tools).
My first advice is to buy the CD (or MP3) if it’s available digitally. 
The Click Removal effect works automatically. The Repair effect is manual so you have to zoom-in on each defect. (The Spectrogram View is often helpful in “finding” clicks.) And in some cases you can zoom-in and use the Draw Tool to re-draw the waveform.
There is a free specialized program called [u]Wave Corrector[/u]. I’ve also used [u]Wave Repair[/u] ($30 USD). Wave Repair can do an audibly perfect job on most (but not all) clicks & pops, but it’s manual. That means it only touches the audio where you identify a defect, but it’s VERY time consuming.
The developer of Wave Repair has a [u]web page[/u] with several other software recommendations and a ton of other information about digitizing records.
See also this Sticky thread re the ClickRepair app: https://forum.audacityteam.org/t/click-pop-removal-clickrepair-software/1933/1
WC
I have yet to find a tool which works automatically without also losing recording quality. I record each side at high sample rate from a top quality cartridge. Its the old principle of rubbish in rubbish out so there is no substitute for getting a good source recording using the best kit you can afford. When I extract each track I find unreasonable peaks by examining the wave form and then zoom in tight on each one. With experience it is easy to see which scratches and clicks will sound bad and which can be ignored. Nearly all of these glitches are of very short duration and can simply be deleted. This is time consuming work but if you are going to spend the rest of your life listening to the track isn’t that worth it? Incidentally I also save each track with the correct meta-data storing the track title, album title, artist, and track number. It is also useful to embed the track number as a prefix to the track title and use a leading zero ( 01-,02- etc.) so that the files can be sorted in track order reflecting the album layout.
Of course if you are more likely to listen only once or twice then move on all this effort would make no sense.
so there is no substitute for getting a good source recording
Usually you’re stuck with the records you’re got. 
using the best kit you can afford.
Personally, I wouldn’t go too crazy. With analog, the quality of your hardware is more critical than digital but I wouldn’t go too crazy because you can spend thousands of dollars on a turntable, cartridge, and preamp, and run into diminishing returns and you’ll never get “CD quality”. If I was buying new equipment I wouldn’t spend more than $500 USD (and I might try to keep it below $300).
Thanks to DVDdoug and others for their replies. I’ll work on it. Happy New Year!
Paul-L’s de-click plugin for Audcaity (free) can also de-crackle, see … Updated De-Clicker and new De-esser for speech - #48 by Trebor