"Mum, I will hoover the lounge"
"Who wants to play frisbee in the back garden?"
"You take the lift and I will take the escalator"
In fact, you 'vacuum clean' the house. HOOVER® is a registered trade mark belonging to Candy Hoover Group. It denotes a particular brand of vacuum cleaner, made and sold by a particular business. The term is not 'generic' to describe all vacuum cleaners.
Also, you play with a 'flying disc'. FRISBEE® is a registered trade mark belonging to Wham-O and denotes a particular brand of flying disc. It is not a generic term and should not be used by all flying disc manufacturers to describe their product.
ESCALATOR was once a registered trade mark, that was used as the brand name for a particular moving stairway sold by Otis Elevator Co. Unfortunately, the brand ceased to be seen 'as a trade mark'. The general public came to regard it as the descriptive name for a moving stairway and not as indicating the trade source of a particular stairway.
A trade mark can be a business's most valuable asset (e.g. think of the financial worth of the trade mark APPLE®). The purpose of a trade mark is to allow consumers to identify the trade source of a product or service, to make associations of quality with that product or service, and to make purchasing decisions based on those associations. If a trade mark becomes a generic term - the common term associated with a particular category of goods or services to which it relates (usually because the product or service has been very successful in the marketplace) - then it ceases to be a trade mark. If it becomes so colloquial that it starts to mean the entire product or service category, then it has become 'generic' and such terms are not capable of serving as trade marks. They are no longer registerable, as they no longer tell you who is behind of the goods or services in issue - who is the source of the goods.
If a brand owner does not adequately protect and police its trade mark, it can become generic, and the owner can lose all legal right to protection. In addition to ESCALATOR, examples of other generic terms that started out as trade marks are YO-YO and (in the USA) THERMOS.
So, what can a trade mark owner do to prevent the 'genericide' of its trade marks?
First, adopt Trade Mark Usage Guidelines and ensure that the business enforces them. For example, the mark should never be used as a verb (e.g. "to Google", when in fact you should say "I will carry out a search engine search using GOOGLE"). Also, identify non-branded products and services by their common names and terms or create one (e.g. "hook and look fastener", rather than "VELCRO®" - which is a brand name and trade mark for a hook and loop fastener made by a particular business). When you use a trade mark, always display the trade mark in capital letters and always use the registration symbol ('®' - assuming the mark is registered) immediately after the trade mark, without any spaces in between. Consider following this with the correct generic term for the particular product or service. For example, "By a HOOVER® vacuum cleaner." Also, where appropriate, use trade mark notices, such as "GOOGLE® is a registered trade mark of Google Inc.". Another common practice in the USA is for trade mark owners to add the word 'brand' straight after their mark, in order to try to keep the mark as being seen and regarded as a trade mark (e.g. "VELCRO® brand").
Second, consider running marketing campaigns to remind the trade and public that your trade mark is exactly that - it denotes the trade origin of the particular goods or services in question - and should only be used in that manner. For example, in 2010, Xerox ran a marketing campaign in the USA, advising users to "photocopy" instead of "xerox" documents.
Third, monitor the marketplace, especially online. As soon as you find examples of generic usage of your trade mark you need to take action to prevent this becoming the norm. Often this is done by contacting those using the term in a non-trade mark sense and asking them to stop - especially the press. Educate them to see and treat your trade mark as unique to your business - something that others should not use unless they are referring only to your business's goods or services.
If you don't look after your trade mark then you will lose it. The law expects a trade mark owner to take steps to prevent their trade mark from becoming the common name in the trade for the product or service for which it is registered. Doing nothing is not an option - or you could end up like KEROSENE, LINOLEUM, TRAMPOLINE and VIDEOTAPE and your brand will become just another 'former' trade mark.